Landing Gear: Struts – Monty the Answer Man Archives

WORN SPOT ON STRUT…
From: ejectr@javanet.com (Bob Runge)
Hi Jim:
I have a worn spot on my Adel right strut. Can these be re plated? Thought I read somewhere that they were too thin to grind. Best regards…….Bob Runge

Bob,
If its just a spot that gets rusty, I would sand it with fine paper, and keep it polished and lubricated. The Adels originally only had a flash coating of chrome. the ELIs have several thousandths of chrome. Recent mfg. replacement Adel strut tubes have more chrome than the originals. Yes, the wall thickness is only about .090 for the Adel strut tubes, too thin to allow grinding. If you have straight cylinders, they could be re-chromed, if proper procedures to eliminate hydrogen embrittlement are followed. If the chrome ends up adding a little to the OD of the strut, you get a side benefit, if there is wear in the brass bushings that the struts ride in, they will probably fit real nice after chroming. If they fit TOO tight, chuck the tubes in a lathe and polish – and polish – and polish…..with 320 wet or dry, until they fit just right.  —  Jim

ADEL STRUT QUESTION…
Subject: Re: Adel Struts
ejectr@javanet.com writes:
Hi Jim: With the struts properly filled, how many inches of strut tube should be exposed?
Thanks Jim. Best regards……. Bob Runge

Bob,
The Swift Operators handbook doesn’t give a figure for the Adel gear. The Adel gear is dependent on the spring installed in it for strut extension. You can also install 1/8″ air valves in the 1/8″ pipe threaded holes in the strut meant for adding fluid to the Adel strut. A few years ago they had some “extra length” springs made up, which I installed, mistake! My struts are only up an inch or two now. (note the picture of the gear on my web site) I have the air valves installed too, but the Adel “O” rings don’t do a perfect job of holding air pressure, my right one leaks the air out after just a few days. The good news is, this is not critical, the gear still absorbs shock as well as a perfect Adel gear. The Adel is rougher than a properly inflated ELI gear, for this reason I don’t run high tire pressure, and don’t like the 15:6:00×6 tires. BTW – the book gives a figure for the ELI gear – 3.75 inches of extension at GW. Oh, the struts are properly filled, when on jacks and fully extended, the oil level extends to the filler hole. The 1946 fluid was AC 3580 what we have now is Mil 5606.  —  Jim

STRUT EXTENSION…
From: Dennis Friedrich (dennisd@televar.com)
Subject: Gear
Jim,
I own 3773K and when I received it the gear scissors were extended almost all the way. Several have questioned the nearly full extension…..what is the correct scissor attitude and what is the method of correcting it? Thanks,  Dennis

Dennis,
I presume you must have the ELI landing gear. The book figure is 3.75″ extension at GW of the airplane. If its fully extended, that won’t hurt anything, but may ride a little hard and will make not-so-perfect landings seem like crashes! Deflating them a little is kind of tricky, since the air is on top of the fluid and if you simply try to bleed them off at the air valve you get a face full of 5606. The right way to do it is on jacks, with the gear “up”. If you lose fluid, you have to estimate how much and replace that amount. I used to have a setup made out of a Swift brake reservoir so I could blow in fluid and air together. The right way to do it is to drain the cylinder, then with the strut flat, fill it completely with 5606, then air it to 3.75″. I prefer nitrogen, but you can use a strut pump. An air compressor with say, 200 psi, won’t cut it. You need 400 psi available, although I think 200-300 psi will service the strut properly. Maybe you should just leave them the way they are! — Jim

ADEL STUT MAINTENANCE…
Bob Runge (ejectr@javanet.com) writes:
My Adel struts have air fittings on them. Do I fill them with oil then pump a specific amount of air into them or do I run just air in them? How much air in either case?

Bob,
Remove the fittings, fill the struts with 6506 with them extended, reinstall the fittings, air, some guys get by with 20 psi. There is no specific amount of air. Originally, the amount of air in the strut was what was trapped above the fluid level. (not much) Mine leak, so I air to about 100 psi, and the left one holds pressure for a while, but the right is almost flat in a couple days. The air valves are “unofficial”, so you are on your own.  —  Jim

HOW TO MAKE AN ADEL GEAR FORK FIT AN ELI…
Jim Montague (monty747@aol.com) writes:
I have taken Adel forks, welded up the keeper bolt hole, (3/8”, I think) and had my machine shop owner friend bore them out for the ELI strut dia. (-.001-.002) The air valve can be located as original with more machining, or re-located near the top of the strut, (like it should have been in the first place) I don’t have any ELI parts, or know of any, but I have some Adel forks.

WE GONNA PUMP YOU UP…  (050399)
Keith Bracht <kab_bjb@skat.net> wrote on the Yahoo! Globe Temco Swift Club…
After some touch and goes yesterday I noticed the right strut had about 2″ of chrome showing and the left was still at 3.75″. Do I need to service the low strut? In the Answer Man archives Jim mentioned a strut pump. Is this something I should get? Who sells them and how much does one cost? Thanks.

Keith:
Most FBO’s have either a strut pump or a high pressure nitrogen bottle for airing struts.  I would hope you won’t need either often enough to need to buy them. A strut pump will need to be capable of 400 psi at low volume. Sometimes you can find these at FBO auctions at very low prices. New? Probably more than you want to spend! Your airline probably uses high pressure nitrogen. Can you taxi in to one of their gates and get a “squirt”? — Jim

BUT WAIT!!! THERE’S MORE ELI LANDING GEAR… (8199)
From: “George N2451B” <gi@globe-swift.net>
Subject: RE: ELI gear
Hi Monty,
Now here is the next problem: While we pushed the Swift back into her hangar the gear (strut) came up a lot. Now I feared that it might come out completely so I let out all nitrogen. Unfortunately we still cannot push the strut back in (we have not tried very hard though in order not to damage anything…) Could it be that it is already sitting on the gaskets? Is there a trick to get it back in? Since my Adel on N2451B already sits low I was thinking of getting new springs for it (or sending it to the states to get it rebuild). Does it make more sense to install an ELI instead if one can still get one? Thanks for your help! Regards, George

George,
Just remove the remnants (if any!) of the scissors (what is the common name for the torque link) and the brake. Then pull the strut out of the upper cylinder. When you get the strut cylinder/fork/axle assy. out inspect the “O” ring inside the outer cylinder. It may be twisted or just dry. Inspect all the parts. If the “O” ring is worn or cut replace it. If it is deformed, it may come back in shape if you soak it in 5606 for a day or two. With a serviceable “O” ring in place, lubricate it with a copious amount of Vaseline (petroleum jelly) and reinstall the strut. The only thing that keeps it from blowing out is the scissors – thus the requirement for a STEEL part. Fill the cylinder with MIL5606 with the strut flat. There is an allen head pipe plug at the top of the outer cylinder which holds the metering tube and also provides a place to put in the oil. You obviously will need a new scissors, contact Joe, sorry I can’t tell you where there are any ELI scissors’ – if the other side is aluminum, you need two. Don’t air the strut until the scissors is installed! With everything in place, air to 3.75″ strut extension. You will need a strut pump or a nitrogen bottle with approximately 500 psi available. (the strut will take 300-400 psi) I also suggest a bolt and bushing kit if there is excess wear. See previous letters on this!

I like the ELI better. It’s much easier to replace the seal etc. It’s also harder to service afterward. The big advantage to the ELI is, when properly serviced, it rides like Cadillac vs. a Model “T” Ford. It also is a little lighter than the Adel gear. (If you folks in Europe are not familiar with the Model “T” – believe me, the ride is ROUGH, kind of like a Swift with Adel gear 😉

…and BTW, if you are going to groundloop a Swift, do it with the Adel gear! The forging blank for the fork is the same, but the ELI has a larger dia. strut cylinder, thus the wall after machining is thinner. Plus, they made a hole there for the air valve, not a good move. I broke one once! (details on request) The forks can be interchanged. (kind of) To use ELI on an Adel, a bushing must be made up with the Adel strut ID and the ELI fork OD (.001″ tight on each) The 3/8″ keeper bolt holes need to be welded up and the fork machined smooth. To use an Adel on an ELI, the fork must be machined to the correct dia. to accept the ELI strut. Don Bartholomew expressed concern about the heat treatment of the welded parts, my guy claims he can take care of that. Another thing – the chrome is much better on the ELI struts.

I don’t know if you can find any, (ELI gear), they are scarce as hens teeth as they say. The ELI also takes different gear doors BTW. (factory type) The so called P-51 gear doors should work on either. My Adel gear on N2431B sits low too – when I rebuilt them I used the “extra length” springs – which was a mistake. The springs are regular die springs available here in the states from any spring shop. I think I would like to. get a set heat treated to maintain their “set”. I’m not sure I understand spring engineering, but I’ve been told a longer spring makes a softer ride. I guess I need to get a textbook and read up on that subject! I have overhauled a LOT of Adel landing gears and it’s not too bad if you have Mr. Cummins book (hydraulic manual – available from Swift Association) and a press to compress the spring while you get the snap ring out. — Jim

STRUT PROBLEM… (8199)
My left gear strut is fully extended and will not compress at all. Even with a bunch of air bled off it is still rigid. I know about the 3.75″ extension but how many pounds of air should be in there? I’ve even greased the chrome but nothing seems to compress it, not even my landings! Thanks. Keith Bracht <kab_bjb@skat.net>

Keith: I suspect the “O” ring is dry inside the outer cylinder. Try putting Vaseline on the strut and jumping up and down (gently!)on the wing walk. You may have to release more air. — Jim

STRUT YOUR STUFF..  (9499)
Subj: Adel Chrome Gear Strut
From: Bob Runge <ejectr@javanet.com>
Hi Jim:
How’s it going? We survived Floyd with just a lot of rain (which we needed) and some minimal gusts. Not too bad. I read in the latest newsletter that the Adel chrome struts were going to be available through Swift parts. They are talking about just the chrome tube…….correct?

Bob,
Yes, that’s just the chrome strut tube — they were getting $400.00 for them – I don’t know how much the new ones will be. To change them requires an experienced mechanic. The spring on the strut needs to be compressed to get a snap ring out, and heat needs to be applied to get the fork off. — Jim

ELI LANDING GEAR…  (11299)
From: Pete King <peetking@earthlink.net>
CC: arbeau@napanet.net
Was there a pattern for the use of Eli gear? — my 665 has them but they seem to be random in their use…

Pete,
The ELI gear was used on many of the Kilo series airplanes. On N80665 it must have been installed later. I had them on N2334B, but they were installed by me. The Buckaroos, which were made around 1950 also used the ELI gear. — Jim

“AIR’IN UP” THE STRUTS… (060200)
Subject: Re: ELI gear
From: joenorton@webzone.net
Jim: Need some info on putting hydraulic fluid and nitrogen in my ELI struts. I know this is not the prescribed way to do so but please tell me if the way I’m doing it will be okay. I put the plane on jacks and let out any air pressure and hydraulic by removing the Schrader valve. I then hook a hose to the opened valve and place the other end in measuring cup with hydraulic fluid in it, lift up on the wheel let it come down which sucks up the hydraulic fluid. I do this until there is about 4oz of fluid in the strut. Close up the Schrader valve and then hook up the valve to a nitrogen bottle. Last time I did this Joe advise me to put in 180lbs in the strut. The result was a fully extended strut. Now I’m going to have to try and let out a little pressure but I don’t think I can control the flow to get down to the 3.75″. I guess my question to you though is this an okay way to get the job done. — Joe Norton

Joe,
I would say that method should work ok. As you know, if a little air (nitrogen) is bled off, you will lose fluid since the air is on top of the fluid. I was always going to relocate the air valve near the top of the strut to avoid that, but never got around to it. Perhaps you could bleed out a little air with the gear retracted. I never tried that when I had an ELI gear, but was told it works. Usually, if the strut is fully extended, but not way overfilled with air, it will work ok. — Jim

LEAKING STRUT… (080600)
Subj: ELI Struts
From: jerrycobb@mindspring.com (JERRY COBB)
Jim,
As the designated caretaker of 3301K (#1294) since 1972, I am asking for ideas in regard to my leaking right ELI strut. Since the resurrection of “Old Hurricane” by Swift Works in 1997, I have been plagued with a strut leaking down over a period of 4-6 weeks. The other strut has never required air. You may recall that this is the Swift that was destroyed by Hurricane Andrew 8 years ago today in MIA and “resurrected” (Charlie’s word). I have removed the plug at the top of the strut and serviced the strut with 1506 per the original Swift manual. When the air (nitrogen) charge continued to leak with no evidence of fluid at the Schrader valve, bottom plug, or on the barrel, I began to tighten the top plug a little more each time that I serviced the strut with nitrogen. I have applied liquid dish soap with a little water added around the top plug, but no bubbles are visible. As I stated, this is a very slow leak. During the a/c rebuild the struts were overhauled. It seems that a long time ago that I had a similar problem and it turned out to be a small leak around the top plug. Any ideas or suggestions would be welcomed. Would an air leak around the barrel seal leave a fluid residue? What is a good way to tighten the top plug?  Thank you for your time and effort in being the “Answer Man” and to Dennis for putting forth the “Electronic Effort”. Best Regards, Jerry Cobb

Jerry,

Gee, have you “only” had N3301K since 1972? I well remember the picture of N3301K and the D’Arcy Swift inverted over Miami. It seems like you have had it forever! With air loss and no sign of fluid leakage it does indeed sound like the top plug is leaking. I guess I would start over and replace the “O” ring and service the fluid, then with the top plug removed, I would clean the threads on the plug by polishing on a rotary wire brush. Also clean the threads in the upper cylinder. Then I would apply some super sealant to both sides and reassemble. (Use something made by Locktite or 3M that will not be affected by hydraulic oil) While you have the chrome strut removed, polish it with 400 wet or dry sandpaper. Remember, when the gear is “up” during flight, a portion of the “O” ring will be at the high point of the gear air and fluid, so the small leak may occur at that time. Does the gear leak down if you don’t fly the airplane? Also the Schrader valve may leak when it does not have the viscosity of the hydraulic fluid acting on it. — Jim

SERVICING THE ADEL STRUT IS DIFFERENT THAN THE ELI…  (090100)
Subj: Landing gear fluid
From: marvin@accesstoledo.com (marvin-h)
Jim, I have done my homework but I would like to confirm this with you. About filling the Adel landing gear with hydraulic fluid. It says to fill the struts with 5606 while the plane is jacked up and the gear is fully extended. Fill with fluid to the top of the filler plug. Since this is exactly backward to what I am used to doing on another brand X airplane it seems strange to me. How about setting me straight. Marvin Homsley N80740

Marvin,
That is right. The only air that the Adel struts are designed to have in them is what is above the fluid level when filled to the level of the filler plug. Some guys discard the filler plug and install a 1/8 pipe air valve and air the strut to between 20 and 100 lbs. If the “O” ring seal is not perfect, the strut will leak down in a short period because there is not much volume. The way most air/oil struts are serviced is with the strut flat, fill with oil, then air to the desired extension. This is the way the ELI gear is serviced. — Jim

WOBBLY GEAR FORK ON THE EARLY ADEL GEAR… (090300)
From: Roy Cook <RCook63133@aol.com>
Jim,  Hello again, hope you are well. I told you about changing the brakes on my GC-1A and I finally got around to it. In the process I found that the left gear needed to be rebotled and rebushed, that went OK, when I got done doing that I found that the gear fork had a lot of movement from side to side, I didn’t measure the movement but I estimate it at about 1/16 to 1/8 of an inch. That seems like a lot of slop. Can you tell me what others have done for this problem. I have had others tell me that plating the strut end to build it up and then grinding it size, is this the way to repair this or is there a better way. Any help you can give me would welcomed. Thanks, Roy

Roy,
Um, rebotled? I’m not sure I understand where the wear is. Most of the landing gear wear limits are given in AD 47-06-01 and AD 51-11-04. Do you have the Adel gear? The early GC-1A’s had a Globe gear that is similar, but different. The chrome strut rides in a brass bushing, which is usually where any wear will be evident. I think Swift Parts has that bushing for the Adel gear, if you have the Globe gear you will have to try and find a used one, I think it’s different. Swift Parts might have a used one. I know Allan Erickson has a set of those early landing gears. <swiftalbon@earthlink.net> If the chrome looks good on your strut that is not where the problem is. That early gear was made by ELI and the chrome is much better than the Adel gear. The Adel gear just has a flash coat of chrome and the early and the late ELI gear have perhaps .010 of chrome. (BTW – the early gear can be identified by welded construction and a fluid reservoir at the top inboard of the trunion) Perhaps someone out there has a set of those early gears (if that’s what you have) and will offer to part with them. — Jim

WOBBLY GEAR FORKPART 2… (090300)
Subj: Re: GC-1A landing gear
From: Roy Cook <RCook63133@aol.com>
Jim,  I think the wear is in the connection of the fork and the strut lower end. Thanks, Roy

Roy,
If the strut is loose in the fork that is unusual nut not a difficult fix. The fork should be removed and a short piece of steel tubing obtained. You want the ID to match the strut, less about .001 or .002. Then the fork should be machined out to the OD of the tubing less .001 or .002. You want tubing with a wall thickness of .062 or less, a couple inches long. Reassemble using heat to obtain a tight fit. Having said that, I went over to Mark Holiday’s hangar and we disassembled one of those early landing gears. They don’t have the brass sleeve like the Adel. There is one brass sleeve about 3/4″ high near the lower end of the upper cylinder and a similar “cap” at the upper end of the chrome part of the strut. To remove the lower end of that type of gear is very easy. Just remove the gear door clamps. At the lower end there are 4 ea. 3/16″ AN426 rivets holding the “guts” in the gear, not shot, just in shear with the clamp holding them in. With the brake removed, pry out those 4 rivets with a dental pick and then the lower end slides out. (The scissors must be removed, and the airplane must be on jacks of course) From your previous description, I presumed the wear was between the lower sleeve and the side of the steel portion of the upper cylinder. Any wear at that point could be fixed by the installation of a little stainless shim stock. At the upper end, there is an “O” ring which should be replaced, it is an AN6227-32. That is the simple fix, if it is necessary to replace the “O” rings on the inside of the bushings, it will be necessary to compress the strut and remove the springs, which is a lot harder job. If replacement of the brass sleeve is necessary there aren’t any parts available, but the lower one could be made from an Adel part by cutting it off the right length and otherwise copying the old part. If you cannot repair your gear using these instructions, I would suggest you hire a knowledgeable aircraft mechanic. — Jim

JUST A DROP OR TWO… (090300)
Subj: ELI Gear
From: Phil Howell <POPPAPOU@aol.com>
Hi Monty:  I realize you have probably covered this else where, but I haven’t been able to locate it. I have a slight oil leak at the bottom of my left ELI MLG strut. It appears to be coming from next to the outer edge of the cylinder. Just a drop or two in 1/2 hr. Need your advice of what to do. I really appreciate your help and advice, not only to me, but to the whole Swift gang. Thanks again, Phil N3313K

Phil,
I wonder if it’s really leaking there, or if it’s leaking at the “O” ring and showing up there? If it is, in fact, leaking at the bottom of the cylinder, it will be necessary to jack the airplane, deflate the strut, remove the brake and scissors, and remove the strut and fork assembly from the gear. Then using heat, remove the fork from the strut cylinder. Next, braze around the lower plug, reattaching it to the cylinder tubing. Use caution to avoid heat damage to the strut chrome. If you can’t do this, or don’t know anyone who can, you might try thoroughly degreasing the strut and applying a little Locktite No. 620 Green. It will fill spaces to 1.5 mills and is good to a temp. of 450 deg. I have never heard of an ELI leaking there, although one run of Adel struts unfortunately, did leak at that point commonly. If you do use the Locktite, be sure to follow their directions. A few hours at an elevated temperature may help set it up. Like in an oven. — Jim

THE PRESSURE IS ON… (100400)
From: Steve Wilson <SteveWlson@aol.com>
Subject: Re: October #3 GTS Internet Update
In a message dated 10/9/00 21:43:49 Central Daylight Time, arbeau@napanet.net writes:
<< The reason that it seals better is the fact that it always has positive air pressure, and that is exactly what an O-right seal wants. Bob Williams from Lansing, MI, has replaced the filler plug on his Adel landing gear with a Schrader plug (i.e. 1/8″ pipe fitting with a valve core) and puts about 25 psi in the strut. I examined his struts and they were the driest Adels I have ever seen. I believe he said they were on there for 2 1/2 years now with touching them! >>

Sorry it took folks so long to catch onto this. Since about 1969 I have been pressurizing the Adel struts. I found that with good struts (meaning no pits) somewhere around 50 psi did the trick (maybe lower would work, I dunno). I have run as high as 85 psi with no problems, but that was with “Quad-X” seals. The only problem is that with higher pressures touchdowns are kinda like landing on ball-bearings if you run more than 25 psi in the tires (remember recommended pressure is 20 psi). It probably depends on the weight of the airplane, but with an 1825 GWT on my stock airplane 25/60 works out OK. — Steve Wilson

STRUT SEAL…  DON’T DO IT!!! (110500)
Subj: Hydraulic Resevoir
From: Bob Runge <ejectr@javanet.com>
Jim, Any harm in putting strut seal in the hydraulic reservoir? Someone suggested I do it. I said “I I I I I I I I I… don’t think so! Thanks. Bob Runge

Bob, Don’t do it! Strut seal swells the seals, the idea is to keep them from leaking. If you have some leaking seals in the hydraulic system, it may stop the leaks in the short term – but the seals won’t last very long. Then you would be faced with replacing every seal in the actuators, downlocks and power pack. — Jim

RON’S IDEA OF FUN…(010101)
Subj: ELI strut fun
From: Ron Williamson <rwwilliamson@earthlink.net>
Monty,
Keeping with this month’s hydraulic scheme . . . what exactly is inside an ELI strut? I have a seal to replace and have never quite understood how the innards work. In my struts, the tapered top plug has an attached tube with a cone shaped end which only loosely fits inside the inside tube of the lower assembly. I’m guessing the large chrome bottom assembly is basically a tube within a tube and the cone thing acts as a crude metering device to reduce the bouncing on those less than perfect landings. I’ve followed the filling directions in the manual and it seems like very little fluid is pumped in before it runs out the top plug. Do you know of a cutaway drawing or any more details on what’s inside?

25 years ago when I bought 40K, the hex drive taper plugs had been rounded out so badly that I had to braze a bolt into the plug to make it into an “outie”. The head is short enough that it clears everything while giving me a good grab with a 6-point socket, but it still requires teflon tape, thread sealer and serious torque to keep from losing pressure. Is this normal? I’ve thought about machining out the pipe threads to straight, facing the top of the strut and using a straight thread plug with an o-ring. But, there’s the issue of how that metering rod thing gets attached. Ideas?

Ron,
The plug at the top of top of the strut is regular pipe plug, a 3/8″ I think, I never could eyeball pipe fittings and it’s been a while! Attached to that plug is the metering valve, which “floats” on a rivet. The only part that usually needs replacing is the “O” ring. I would think if your pipe threads are damaged or corroded a pipe tap will clean them up. If the plug itself needs replacing you will have to look how the original is assembled and if you have the capability to duplicate the rivet. I can’t give you great detail on this point because I haven’t looked at one for years and I don’t remember everything! As long as you have the metering rod plug removed just fill the strut up completely with 5606. (with it flat) Then later, when reinstalled on the airplane, fill it with nitrogen to the 3 3/4″ figure. — Jim

STRUT STUFF…(010401)
Subj: Servicing ELI struts
From: Sam Swift <Flyboycpa@aol.com>
I have a question about servicing the struts on 3760K. I have the ELI (air/oil) and am pretty clueless about what to do to service them. Upon each landing and subsequent taxi back to the hangar, both struts have compressed with about 1.5 to 2 inches of chrome showing. At the end of each flight, I lift both wings back up to bring the struts “up” while the plane is hangared. My question is this–how do I go about adding air or oil (or both) to the struts to get them where they ought to be and how do I know which, if either, needs to be added the most and in what quantities. Additionally, is it just regular air or nitrogen?? Thanks for the help, Sam Swift 3760K

Sam
I would suggest just adding nitrogen until the struts are extended to about 3 or 3 1/2 inches. The book says 3 3/4″ at GW. You will be guessing that the person who last added 5606 got it right. If you ever have occasion to remove the landing gear from the airplane you can fill them with fluid, then air them when reinstalled. The book procedure is kind of screwy, but I just filled them up with fluid with the strut flat. Adding air or nitrogen is somewhat difficult because the air is on top of the fluid. Nitrogen is preferred, but a strut pump will work too. I used to have an inline reservoir which I would fill with 5606 and blow in fluid and air together. Caution – if you try something like this, be sure the reservoir won’t explode with several hundred pounds of air pressure, and get it out of there before you air up the strut. I think your struts are not too far off. If they never bottom out, perhaps just leave them the way they are. I would guess your ride on the ground is pretty good! — Jim

ELI LANDING GEAR PRESSURES… (010501)
Subj: Struts
From: Ron Williamson <rwwilliamson@earthlink.net>
Monty, I did see the question that Sam Swift asked about ELI gear, and I’d like to add my opinion. I also have the ELI gear. I’ve been using 160 psi as the nitrogen pressure when the gear leg is fully extended. I fill the strut per the instructions and then put in the plug. I start the nitrogen using a 2000 psi bottle and regulator set at 160 psi. As the pressure builds up, I put a jack under the jackpoint to let the strut extend fully under the pressure. Then, shut off the nitrogen, disconnect and let the jack down. The strut then collapses down to the desired setting. I’ve never been able to get the gear to set properly by just increasing the pressure until it gets to the desired 3 inches or so. My gear always sticks a little when it’s just sitting still. When cranking the pressure up to 250psi or more to get it to the right level, it’s way easy to overpressure and then it’s extended too much. As you know, there’s no graceful way to release the pressure since the Schrader valve is below the fluid level! When moving, with some vibration, it works normally and gives the nice cushy ride. I’m sure it’s simple to calculate the amount of strut compression using Boyle’s Gas Laws, the internal volume of the strut at full extension, the cross sectional area of the strut, the weight on the gear and the ambient temperature, but, I’m an electrical engineer so I took the experimental approach. The analytical method is left to the more academic among us. — Ron

AD 58-10-03 CONCERNS… (010501)
Subj: GC-1B (AD)
From: Michael Ward <Michael.Ward6@PSS.Boeing.com>
Jim, Looking over a 1946 Swift to purchase and came across a potential problem. 58-10-03 is an AD that checks the clearance between the gear strut and the side brace over-extention external stop. Apparently if the internal stop is in its proper place the external stop will have a clearance of 1/32″-1/8″. The Swift in question has no clearance on either strut and the logs say that all AD’s have been complied with. The AD states that it covers all Swifts with “Adel aluminum forged torque knees”. The struts on this Swift are Adel, but they are the Air-Oil not the spring oil. I do not now if the air-oil has the aluminum forged torque knees that the AD is covering. After reading some earlier posts concerning struts, I geuss my question now is weather or not I am dealing with the Adel or ELI strut. How do you tell them apart if the I.D. tag is no longer legible? Any help is appreciated. Regards, Michael Ward

Michael, I’m puzzled, all Adel struts are spring-oil. The aluminum scissors (torque knees) will physically fit on an ELI gear, but they are not legal. All that holds the fork to the ELI gear is the torque link. (and brake hose!) If the torque link breaks, you just lost the lower part of the gear. The steel ELI torque link has never been known to break. Put a magnet on the torque link and determine if it is steel.You should enlist the help of an experienced Swift mechanic. Can you send me a .jpg picture of the gear? If in fact it is an Adel gear, a positive check of the internal stop is to remove the external stop completely. Then if the internal stop ring is broken the scisssors will extend almost vertically. The ELI has a Shrader valve valve in the fork. The Adel has a filler on the side of the strut, a 1/4″ pipe plug. The Adel has the aluminum scissors. (torque link) The Adel has a chrome strut diameter of a little less than 2″. The ELI strut diameter is over 2″. Compare to the parts catalogue. You should not consider buying a Swift without having a knowlegeable Swift mechanic look at it. — Jim

ADEL LANDING GEAR STRUTS… (020201)
Subj: Adel Struts
From: Bob Webster <bob-jewell@wk.net>
Hi Jim, I just thought I would throw in a side note on Michael Ward’s question on the air in the Adel struts. This is the long way around but Charlie Cummins got this on the advice of Bill Commings on putting air in the Adels. You pull the plug on top and put in a Schrader (sp) valve, after the normal servicing of hydraulic juice. Then you give it a shot of air from 40 to 60 psi. Charlie said that he had a buddy that was an engineer who attempted to explain it in engineer talk to no avail. The guy sold him to forget about the details and just do it. It somehow affects the spring rate when it is done. Also, and again this doesn’t make sense, but it makes the gear softer when encountering Mom Earth. I do it on my bird and I can tell the difference as does Charlie in Booger. He also says it helps on birds with tired springs and gives them a slightly new lease on life. So in the long run Michael isn’t far off. You make it an air-oil-spring gear. Works good, lasts a long time. Keep up the good work. Bob Webster

Bob, Yes, I do the same thing but I did not want to complicate the answer to Michael’s question. As it turns out, the airplane has ELI gear. — Jim

LEFT STRUT PROBLEM ON ELI LANDING GEAR…(030401)
Subj: ELI Gear
From: Michael Ward <millerk@gte.net>
Monty,
I recently bought N3773K and I am having a little problem with the left strut. After landing on roll out I applied brakes firmly to make the first intersection. Just at the end of the braking my left strut compressed completely. On previous postflights I have noticed some leakage from the strut, but the 3.75″ measurement was never degraded. There is no damage that I can see, but I imagine that the seal is most likely blown out. My main question is to ask for the part number of the lower seals on the ELI struts since the service information that came with 73K only had info about the Adel gear. Also I have noticed that the fluid that was leaking was not red. Was there another hydraulic fluid other than 5606 that was used in ELI gear? Regards, Michael Ward

Michael,
The seals are available from Swift Parts. It is just a simple AN6227-35 “O” ring in the ELI gear. I used to have ELI gear on a previous Swift that I owned. I had the same thing happen to me once. Since all the air was gone from the strut, I removed the scissors (on jacks of course) and removed the strut and fork assembly. The “O” ring had gotten dry and rolled, allowing the air to escape. I lubed up the “O” ring with Vaseline and refilled the strut with 5606 and aired it up. I never had to service that gear again! Of course, the proper thing would be to replace the “O” ring. Old 5606 sometimes has a yellow appearance, but someone may have used regular engine oil or jack oil in your struts. There is no good reason for this, as 5606 is not much more expensive than engine oil and it may be cheaper than hydraulic jack oil. —  Jim

HYDRAULIC FLUID LEAK… (040101)
I have a trickle of hyd fluid which comes out of the “set screw” in the gear leg (screw holds the bronze sleeve in place). I had correctly installed the soft aluminum washer when I overhauled the gear leg. Question is — can I remove this “set screw” so I can apply a bit of sealant? With the gear up on jacks, if I remove the “set screw” can the bronze sleeve move? Steve

Steve: The sleeve can’t go down, there is a snap ring below it. I doubt if it could go up by itself, although there is really nothing holding it in place with that set screw out. (gravity and friction?) Just pull the set screw out and seal it with something that is impervious to 5606. — Jim

SCHRADER VALVE ON ADEL LANDING GEAR… (040201)
Subj: Adel landing gear
From: Geroge Rodda <garodda@compuserve.com>
Jim;
Recently there was an article about adding a schrader valve on the adel landing gear strut so that it could be pressurized. If I misunderstood the article, please let me know as I ‘m getting ready to install new struts and bushings on our plane. If this is a worthwhile procedure, please advise me. Thanks, George Rodda N3244K

George
That is a worthwhile idea. You can buy 1/8″ pipe air valves in any hardware store for 2 or 3 bucks ea. If your struts are tight, they will retain air. Some guys only use 20 psi. If the springs are weak, you can use 100 psi or more. My right gear never has held air for more than a few days, there is too much clearance between the brass sleeve and the chrome cylinder. There is not much volume in the Adel – so any leakage will be noticeable immediately. The Adel “O” ring is a little small so it might be a good idea to cut a deeper groove and install a thicker “O” ring, but don’t do something like this unless you understand what you’re doing. — Jim

BUT WHAT ABOUT A CLUNKING SOUND??? (050201)
Subj: Clunk, Clunk
From: edlloydaustin@juno.com (Ed A. Lloyd)

Jim, I’ve been meaning to ask this for some time and keep forgetting it. When I taxi my Swift on a grass strip that’s a little bumpy, there is a noise from one or both main gear at various times. We have discussed it around the hangar and I’m told it is the tail wheel strut. I know when the tail strut makes a noise and it’s easy to tell the tail strut from the main gear. When the main gear strut is fully extended, and the scissors stop block has the required clearance, does the silver soldered ring on top of the chrome part of the strut come in contact with the top of the main bushing in the strut? If it does, then this explains the noise I hear. I have flown Duane Golding’s Swift and it has the same noise as mine. When I was towing Dorothy’s “New Swift” today, her gear is making the same noise. Please try and settle this “discussion” item for me. Cheers…….Ed

Ed,
That internal stop ring is probably what you’re hearing. Is it any wonder those rings break off occasionally? — Jim

CLUNK, CLUNK, PART II…(050201)
Subj: Clunk, Clunk
From: edlloydaustin@juno.com (Ed A. Lloyd)
Thanks Jim, you confirmed my suspicions. What would be wrong with putting an ‘O’ ring or a Quad ring around the chrome portion of the strut, at the top, to absorb the shock and stop the noise. That way there would be no metal to metal ‘clunking’ and it should act to absorb some of the shock on the upper stop ring. Cheers……….Ed

Ed
An “O” ring would probably not last too long, then you would have rubber fragments in the strut. Maybe a teflon ring?? I will give it some thought. — Jim

ELI STRUT INFLATION… (060401)
Subj: ELI Strut Inflation
From: Michael.Ward6@PSS.Boeing.com (Ward, Michael B)
Jim,

Recently replaced seals common to the ELI struts on N3773K. Ever since, I have been trying to figure out the right formula for proper chrome extension (ie.3.75″). I have tried several way, but all have been hit or miss and I would like to have a system that works “every time”. The one thing I have not done is to have the tail up on a stand when inflating the struts. Maybe this is what’s causing the inaccuracies. Let me know if you have any tricks up your sleeve. Regards, Michael Ward

Michael
I must confess when I had a Swift with ELI gear I often used a hit or miss method. Usually, once I got it right, it lasted for years so I didn’t worry about it too much. If you get the struts overinflated you can let a little air (nitrogen) out and get a face full of 5606. (cover the Schrader valve with a rag) There are several “tricks” — lube the struts up with Vaseline so the “O” rings slide more freely on the strut. Put jacks in place and jack to full strut extension. Then adjust the nitrogen regulator to a set value, say 250 pounds. Then remove the jacks. If you need more strut extension, repeat, only use more pressure. (the value varies with individual setups) Once you get a pressure value that works for you can repeat the procedure. — Jim

STRUT LEAK STOP IDEA… (090201)
Subject: Re: Leaking Strut
From: Phil Howell <POPPAPOU@aol.com>
Jim,
Regarding the note from Mile Whitt concerning the leaking LG strut, I had a similar problem on my left ELI strut. I fixed mine as follows: Extend the strut and carefully drain the fluid and air from the strut via the scrader valve. Mix up a solution of 2oz (by volume) of Flocked Cotton Fiber and hydraulic fluid, pump the mixture into the strut. Continue to refill the strut with the proper amount of fluid and air. Over time the fibers will settle to the bottom of the strut (they sink in hyd. fluid) and slowly fill the cracks. This worked great for mine and the cotton fibers “should not” harm the rest of the system. The fibers are available from Aircraft Spruce, Ph 877-477-7823, P.N. 01-14800, 1 lb. $1.95. The fibers are used as a thickening agent in epoxy. It goes without saying, “use this advice at your own risk!” Phil N3313K

Thanks, Phil — I had not heard of that problem with an ELI strut. Usually, it’s the recent production Adel struts that have that problem. — Jim

STRUT LEAK STOP IDEA #2… (090201)
From: Rick Stroud <Rick.Stroud@tbe.com>
Subject: Landing Gear Strut Leak
I had a the same problem with N78280, the strut leaked by the bottom plug. We (Jim Thomason, my long suffering mechanic) solved the problem by removing the landing gear and taking it apart. Cleaned the strut inside to remove any oil. We then poured slow drying epoxy into the strut (enough to cover the entire plug at the bottom. We then cut a valve out of an old tire and clamped the whole thing in a press. We put about 80 psi of air in the strut while the epoxy cured – we left it overnight. That was about 5 years ago and no leak so far. Simple and lots less expensive than a new strut. Hope it helps, Rick Stroud

STRUT LEAK STOP IDEA #3… (090201)
Subj: Gear Strut Leaks
From: Jim <jimlinda@spacestar.net>
Hi Jim,
I saw the posting on the strut leak and thought I would pass along my experience with the problem to date. I have had one that leaked since new. I tried to clean the outside and add epoxy to the bottom of the cup around the edge of the cup to stop it from the outside, it worked for a week. Then I took the strut out, called Loc-tite and found that a green Loc-tite might work. I cleaned it out and washed it with everything known that will cut the 5606 and then poured the Loc-tite into the strut. It set-up so fast that I wasn’t sure that it could have penetrated the leak area. It didn’t at first and then after a month it quit leaking and stayed that way for a couple of years. Now it’s leaking again. I’m of the belief that there are only two ways to fix it. One, replace it with a new correctly made one. Two, find someone that can work miracles with silver solder and remove the plug, clean it and replace it with the proper process. The second choice is to risky in my opinion on a finished strut and I worry about embrittlement etc. I’m just going to bite the bullet and replace mine this winter when there is no flying to be done. — Jim

STRUT LEAK STOP IDEA #4 (090201)
From: Porter Houston <porter.houston@home.com>
Subject: Re: September #1 GTS Internet Update
Ref: Main Gear strut leaks at the bottom.
The fix is real simple.
Remove Strut, Clean out very good especially at the seam where the plug meets the strut tube. For the final clean out use Loctite Primer ( it’s in a yellow spray can). Dry out real good with compressed air. Pour just enough Loctite 290 inside the tube to completely cover seam. 290 is very thin and will wick into the seam area ( IF IT’S CLEAN). Let it setup over night. Do the same thing on the outside of the tube at the bolt hole seam. It worked for me. I recommend this even for new struts. — Porter

STUCK STRUT… (100401)
Subj: Gear strut
From: Don Woodhams <biplane@btc-bci.com>
Hi Monty, We have a gear strut that seems to be froze, strut will not extend on jacks.It won’t move so the snap ring can be removed. If we removed the bushing locking bolt will the strut then come out of the upper housing. If not how will we remove the , we think bent , strut. Thanks for all your advice. Don woodhams

Don
If you remove the bushing locking bolt probably nothing will happen. Place a 2 1/8″ x 6 1/2″ piece of tubing (suitably split) over the strut. See the Commings Manual. If the brass sleeve won’t push up, I would remove the landing gear from the airplane. Place the gear in an arbor press and attempt to compress it. You need to push the brass sleeve up in the cylinder about 3/8″ to remove the snap ring. Be sure you have removed the keeper bolt! If the strut is bent so bad you can’t do this you are in “experimental” mode and you will have to rely on your own ingenuity. At this point it is a “sledge hammer” operation and may require a LOT of pressure from the hydraulic press, but I have never seen one that wouldn’t come apart eventually. Mark Holliday had an Adel strut that had previously been assembled with an oversized sleeve and it took several days of effort to get it apart. Mark left the gear in the airplane and applied pressure and blew the strut out. I would use hydraulic pressure or a grease gun, with several grease cartridges available. Caution: If you use air pressure to blow the strut out, it may take 500 lb of pressure or more and create a very dangerous situation. — Jim

FLAT STRUT… (100401)
Subj: flat strut
From: Phil Nussbaum <joem@totalseal.com>
Dear Monty,
we are in the throws of buying a swift. One of the things I found on my initial prebuy was that the right strut was much lower than the left. A look in the parts breakdown wasn’t that much help unless the spring is gone soft or it has broken. I don’t think there is an inch of piston showing. Don’t know how long the present owner has been flying it this way. I would not sign it off for ferry because I was afraid of increasing any internal damage that might already exist. Of course the gear door attach arms have been scraping the strut itself as well. This airplane had a low speed groundloop in which the left strut was replaced don’t know if it material to this or not. I need an experts best guess as to what is going on with the right strut and if I was correct in not signing it off for ferry either. Thanks Phil Nussbaum

Phil
I presume you are talking about an Adel gear. If it is an ELI gear there is no spring in it and raising the level is a simple matter of airing it (with a strut pump or nitrogen bottle) The ELI should not be flown with low strut extension. Weak springs are common in the Adel gear and are not critical. When the gear is hanging down, in flight or on jacks, the spring will give full extension. The gear will only bottom out in a very hard landing. A quick way to get more strut height is to install a common 1/8″ pipe threaded air valve in place of the filler plug on the strut and fill the strut with air or nitrogen. You can get an air valve like this at any hardware store for about $2.00 If the “0” rings are old the strut will not hold air pressure for very long. Regardless, a low spring in the Adel gear is not critical. — Jim

STUCK STRUT UNSTUCK… (110201)
Subject: RE: Don Woodhams <biplane@btc-bci.com bent gear
From: “Owen, Larry” <Larry.Owen@Tenethealth.com>
Hi Denis
Under the “Been there, done that” heading….. several years ago….. after ground looping and bending the left gear, it took a press and some very gentle heating with a propane torch to get it to release. Heat it with a “spreader” on the flame and keep it moving. You don’t need to get it hot, just warm all over, as you only need a few thousands expansion to get it to release. Hope this helps….Larry Owen N78287 El Paso, Texas 915-577-6832

CAN’T GREASE IT… (010302)
Subj: Main Gear Pivot Point
From: Doc Moore <darladoc@sport.rr.com>
Jim:
Can’t get left main zerk fittings to take grease… front or rear. Have pulled fittings and they’re clean. Have cycled gear up..45.. and 90, trying at each spot. Still won’t take grease. Am going to heat the trunion housing with my heat gun this afternoon to try to soften old grease to see if thats the problem. Its ELI gear… could the bushing have spun? If I elect to remove in order to clean and inspect are the four bolts on the front and 4 on rear holding the assembly in going into nut plates or just plain nuts? My AI is going to submit the 337’s on the JPI Instruments per your suggestion. Thank you for your help, Kindest Regards, Doc Moore

Doc
The ELI gear, when manufactured, had no grease fittings. So what you have is field installed by who-knows-who. Are they the flush fittings for a needle point grease adaptor? I suspect that the brass bushings in the aluminum trunion caps were not grooved for grease retention. You might try “wobbleing” the gear while the airplane is on jacks to get some grease in there. What you are experiancing is not unusual. I had a set of ELI gear and installed some grease fittings in the trunioin caps but never could get much grease in there. I guess the way the manufacturer of the gear intended, you must remove the 4ea. 1/4″ bolts front and rear and grease the bushings ny hand. Yes, there are nut plates for these bolts. — Jim

AIRIN’ UP THE STRUTS…(030302)
Subj: N80572
From: Bill Doty <wdoty@earthlink.net>
Jim, I am ready to air (nitrogen) up the struts but have trouble figuring out the instructions for ELI gear. Need to add hyd. fluid but I am not sure of the process! Refers to upper plug and lower bleeder. Believe the upper plug is at very top of strut but the bleeder is in question. I have located the plug inside bottom of strut but seems to me it would drain the strut!? Maybe a quick note would help to get past the “senior moment”… Also, the high psi air valve stem destroyed its self on removal ! Broke off inside the brass housing. Any idea where a new housing could be purchased? I have the stem on order. The good news is that the gear and flaps cycled and all the lights are working !!!!!! Thanks, Bill Doty

Bill
Read “Landing gear – struts” in the “Monty the Answer Man” archive. You have me confused when you say “broke off in the brass housing” – The air valve for the ELI gear is in the aluminum fork. I don’t know of a brass housing. Maybe someone in the past has installed a thread repair……? As long as you are starting from scratch, with the strut flat, fill it with 5606, then air to 3 – 3/4″ extension. — Jim

AIRIN’ UP THE STRUTS PART II…(030302)
Subj: N80572
From: Bill Doty <wdoty@earthlink.net>
Jim, I have printed out the pages in “landing gear/struts” and will read them. The Valve I referred to ,as brass, is the Schrader valve. It is in the aluminum fork. Have new ones on order from Swift Parts. When you say “flat”, I assume you mean “no air”. Adding oil to the top hole, how do I know when it is full? I still am in doubt as to what is referred to in instructions as “bleeder valve”. Will read the archives and get back to you, if still in a state of confusion. Thanks, Bill

Bill
With it flat (no air) just take one bolt out of the scissors, presuming the brake line is removed, the whole lower unit can then be pulled out. Fill it up with 5606 thru the hole in the strut. Reinstall it with vaseline on the “O” ring. You may have to raise the tail and level the airplane to get the metering valve which “floats” on one rivet to hit the hole in the strut when reinstalling. If the landing gear is removed from the airplane, the metering valve van easily be removed, it can’t be removed in the aircraft. You might have a small pipe plug on the bottom of the strut which could be called a bleeder valve, usually it should not be necessary to remove this. — Jim

DON BARTHOLOMEW IS HERE WITH: AIRIN’ UP THE STRUTS PART III…(030302)
From: Don Bartholomew <diamondswift@earthlink.net>
Subject: air valve
Bill,
If I read your email correctly, the valve stem core (the part that comes out of a tire stem) broke when it was being unscrewed from the housing (brass) of the schrader valve, and part of the stem remains in the housing. If this is correct, you can remove the schrader valve with a deep 7/16″ socket. It is better to use a six point socket to reduce the possibility of stripping the hex. Once that is out, just install a new schrader valve. Check with Swift parts, I think they have them. Also, once the schrader valve is removed from the strut, you may be able to push the remaining piece of valve core out with a small punch (from the strut side). If the threads in the housing are damaged, you can get a thread chase for a standard tire valve (Napa store) and clean the threads. I imagine you have already looked at the archives, but take the bottom plug out, compress the strut, and pour fluid in the top until it runs out the bottom. The strut has to be filled a certain amount before there is enough fluid to fill a cavity and overflow. The excess is what runs out the bottom plug. – Don

ELI LANDING GEAR “O” RINGS…(030403)
Subj: N80572
From: Bill Doty <wdoty@earthlink.net>
I am resealing the struts (eli). Old seals appeared to be a single “O” ring 2.375 ID, 2.750 OD X .187 thick. The ID was flattened due to age. Received new seal kits from Swift Parts today and got something else ? Each kit has 2 rings, approx. correct size, but not “O” rings. Each ring has 4 concave sides. Kit number on package is S145X. Also received seal kits for lock down cylinders. Several “O” rings but have not disassembled a unit yet, so nothing to compare to. Any advise on what I got or what I need ? Thanks, Bill

Bill
It sounds like they sent you the seal kit for the Adel gear. The seal kit for the Adel gear used to be S145 – the x denotes the quad x “O” ring I would guess. The seal for the ELI is a simple AN6227-35 “O” ring. When reassembling those parts have your Commings manual handy and coat the “O” rings with vaseline. — Jim

MORE ELI LANDING GEAR “O” RINGS…(030403)
Subj: Re: N80572
From: Bill doty <wdoty@earthlink.net>
Jim, I will contact Swift Parts Monday and return their high dollar seals. They only charged me $8.25 each. Probably correct price but wrong parts. Is there anywhere else to get the “O” rings if Swift doesn’t have them ? Bill

Bill
That is a common “O” ring – the AN6227-35 – and any aircraft supply place should have them. I always believe in giving Swift Parts the business, but Aircraft Spruce gets $2.25 ea for AN6227-35 “O” rings. — Jim

YET EVEN MORE ELI LANDING GEAR “O” RINGS…(030402)
Subj: Re: N80572
From: Bill doty <wdoty@earthlink.net>
Jim, Good Morning, I just talked with Steve @ Swift Parts about the strut seals for ELI gear. He says the “X” shaped rings he sent me are what they have been using , since he was there. 2 rings in a pack are 1 for each strut. I have the “O” rings (AN6227B-35)arriving from Air Craft Spruce today also. Your opinion ? Which would you install? Bill

Bill
I have no experiance using the quad rings for the seal in the ELI gear. If they physically fit, they probably will work OK, but the regular AN6227-35 “O” rings work fine and many last 10 years or more. It’s your call, I would use the AN6227-35 “O” rings. — Jim

WEST COAST SWIFT EXPERT DON BARTHOLOMEW WEIGHS-IN
ON THE O-RING ISSUE…(040102)
From: Don Bartholomew <diamondswift@earthlink.net>
Subject: O rings
I suggest using the regular orings. I have used the quad type and they work fine…….until you start flying and working the strut. They are such a good seal, the strut is to dry on the outside part of the quad and they will roll and leak when the strut goes in and out. The quads are great on a rotating part (actuators) but not as good on sliding parts. This has been my experience anyway. Don Bartholomew
Monty says…
Post-flight, a finger full of Vaseline can be spread around the strut where it disappears into the upper cylinder. That may sound cumbersome, but we used that technique on the 707s at NWA for years. Also, after an overnight, we wiped the exposed portion of the strut down with 5606. — Jim

MORE ON THE O-RING DISCUSSION…(040102)
Subj: O-Rings
From: Steve Roth <Swift97B@aol.com>
Many of us found the Quad-X rings superior to regular O-Rings since they provide more sealing surfaces. They are not approved for aircraft (same materials, etc. — so, what else is new)! So, to avoid supplying non-approved parts, Swift Parts would include the legal O-Rings and the Quad-X rings to “do with as you like”. Steve at Swift Parts is correct — they have been supplying the Quad-X. But, they are supposed to send you the aircraft O-Rings also. That’s the full story. Hope that explanation helps. — Steve Roth

ELI LANDING GEAR…(090102)
Subj: eli gear?
From: Sam Klippert <sam@olypen.com>
Howdy,
Your giving so much good advise to so many people I’m starting to feel left out so I came up with a question for you. My neighbor is just about finished with his rebuild and the question of how much air should he put into the struts. The ELI gear doesn’t have a spring so it only uses air and hydraulics. Every time we check the pressure we loose a little of the hyd oil. It only holds approx. 3/4 cup, and we have to remove the wing strap band. Most people would say to put in enough to make the ride feel good, the trouble is after a few squirts of air the hyd fluid level is now low. I’m hopping you have a psi number that we should start with to get us in the ball park. Thanks very much for being there for all of us. Sam Klippert N80924

Sam
There is no reason to check the pressure! From memory, the book says to inflate the strut to 3-1/2″ at GW of the airplane. It is not very convenient to air the strut with people and baggage on board, so I simply air the strut up “gently” to full extension with the airplane empty, then adjust it if it is too high later. You are right that every time you try to add or subtract air from the strut you lose hydraulic fluid. Try to minimize the loss but if you lose too much, you will have to start over and service the strut with hydraulic fluid. When I had ELI struts on my Swift, I had made up an in-line container which held 5606 and blew fluid in with the air when I added air. (nitrogen) To recap, start with the proper amount of fluid in the strut then air it “gently” to (almost) full extension. That is close enough for government work! — Jim

YELLOWISH FLUID IS NOT THE “OCCASIONAL DRIP”…(OCT 02)
Subj: Swift question
From: Sam Swift <flyboy cap@aol.com
To the Jims (Thomason and Montague),
I am noticing on my chrome portion of my main landing gear struts that I have a “yellowish” fluid on them. Also, below my right gear actuator (in the wheel well), I have a reddish-yellowish fluid that occasionally drips onto the hangar floor. I am accustomed to seeing an occasional drip (especially in the winter) from my normally red 5606, but this yellow thing is confusing. Does 5606 turn yellow upon the presence of moisture?? If that is the case, what is normally necessary to fix this (i.e.-purging and replacing all of the 5606 out of the system, actuator o-ring rebuild, etc.)?? Thanks, Sam Swift N3760K

Sam
Old 5606 normally turns yellow from moisture accumulation. The gear retract system is self bleeding but if you don’t have any major leaks the fluid gets old. The fluid in the struts never gets changed. The old fluid can be sucked out with a suction bulb and a length of tubing and new fluid installed thru the plug on the side of the strut. The brakes are a dead end system and they should be bled periodically to get fresh fluid throughout the system and get rid of accumulated moisture. For more on this subject see “hydraulic system” on the Monty the Answer Man Archive on the Swift site. — Jim

DIFFERENCE BETWEEN ADEL AND ELI LANDING GEAR…(NOV 02)
From: Paul Chandler <paulisa@voltage.net>
Subject: Re: Swift S/N 71
Now for questions—What is the difference between ELI and ADEL gear? Is one better than the other ? Is there complete gear available anywhere? and what kind of $$$ are we looking at. Also did any other aircraft use the same gear as the Swift?

Paul
The Adel gear was used on most Swifts. The ELI was used on the “Deluxe Swifts” which were the 1946 “Kilo” series. (N3200K – N3811K or thereabouts) The ELI was also used on the Temco Buckaroo. The Adel is considered a little stronger and it is a little heavier by a pound or two. The ELI, when properly serviced, gives a Cadillac ride as opposed to the Model “A” ride of the Adel gear. The ELI is a true air/oil strut with high pressure air or nitrogen over Mil 5606 hydraulic oil. The Adel has a spring and oil inside, very little air. The ELI has several design faults. The Schraeder valve for filling is near the bottom of the strut, so you cannot bleed off air without losing hydraulic oil. The trunnions cannot be greased unless you remove the entire gear from the airplane. Servicing the ELI seems to be hard to understand, I continually get “how to?” mail on that subject. The Adel gear is a little difficult to disassemble and replace the “O” ring seals. To get it apart requires heat to remove the fork and a press to compress the spring. I prefer the ELI gear, but I have the Adel in my Swift! Local Swifter Harry Lyon has a set of Adel gear he will sell for $1,000. I have seen ELI gear for sale at prices of up to $2,000/pr. A few airplanes used a modified Adel landing gear, notably the “Texas Bullet” but none used a landing gear that was interchangeable with the Swift gear. — Jim

MARV’S GREAT GEAR EXPERIENCE STORY… (MAY 03)
Subj: gear strut overhaul
From: Marvin Homsley <marvin@accesstoledo.com>
Jim, I have a question then I will give you some of my story on overhauling my landing gear struts. First, I have the gear disassembled and want to add the second “O” ring to the brass sleeve as suggested in the maintenance manual. I think the manual is referring to machining another “O” ring groove into the top of the brass sleeve on the “outside”. I would like to know if anyone has ever added another “O” ring just slightly above the one located on the “inside” also. It seems like a second one inside would help prevent leaks just like the second one on the outside. Would this interfere with the way the hydraulic action of the landing gear works ? — Now for my great gear experience story. I do nearly all of my own work on the Swift but this job has sort of intimidated me until now. The directions in the maintenance manual about making a cuff out of aluminum sheet works fine. Even the bouncing up and down on the wing to compress the strut works fine. The bottom retaining clip comes out as advertised and now the real work begins. Pulling the strut down and out of the landing gear leg took some moderate coaxing with a mallet because the brass sleeve had not been moved in 50 years. Now separating the chromed strut from the lower gear could have been a problem. Another manual tip was to use a small jack between the axle and the chromed strut and it worked fine with a lot of help from a hammer. Gear number one was done but gear number two was a lot more stubborn. No amount of bouncing on the wing would compress the strut to get the bottom retaining clip out. I had to remove the entire gear leg from the airplane. A hydraulic press did the job and I got the retaining ring out. Then when I released the pressure on the hydraulic press the strut did not expand and come apart as it should. It was stuck but good. Now there is a problem because if that big spring inside blows the gear leg apart suddenly that could be dangerous. You have to see one of these springs to appreciate how strong they are. To prevent any damage I tied a rope around the axle and to the mounting flanges on top of the gear and left just a little slack in it. Beating on it with a hammer only separated the two about a quarter of an inch and would not move any further. My gear has the air pressure inlets on the top so I tried air pressure and a hammer and that did the trick. It came apart like a cannon going off. If not for the rope it would have flown across the hangar. One more thing, one of my chromed struts was OK and the other was junk. It was deeply pitted and rusted and as we all know, not rebuildable. I ordered a new one from Swift Parts. Now all I have to do is have the machining done on the brass sleeves and put it all back together again. Anyone can do that. See you in Athens, Tn. next month. Marvin Homsley N80740 marvin@accesstoledo.com

Marvin
If you are going to put an extra groove in the brass sleeve for an extra “O” ring it should be on the inside. The “O” ring on the outside is static and does not wear or get deteriorated. Having said that, I’m not sure an extra “O” ring is a good idea. If the “O” rings do not get lubricated from the hydraulic fluid they roll and do not last very long When disassembling the gear you must have had a bent strut. Sometimes I’ve had to cut them apart with a hacksaw. Blowing the strut out with air is very hazardous and not recommended. Install a grease zerk in the 1/8″ pipe thread where you had the air valve and pump grease in and you will find that works much better and is much safer! Jim

MORE ON THE LANDING GEAR STRUT OVERHAUL STORY… (MAY 03)
Subj: gear strut overhaul
From: Marvin Homsley <marvin@accesstoledo.com>
Jim, thanks for the tip about not using air pressure to blow the strut apart. I knew it was hazardous but did not know any other way. The trick of using grease is great. I wish that had been in the maintenance manual. I am really looking forward to having a Swift that lands normally again. When you are landing on the springs only it lands like a pogo stick. Thanks again. Marvin Homsley

Marvin
I should have mentioned, get a couple of fresh grease cartridges, it will take a lot of grease. You can get cheap grease at Wal-Mart etc. for a couple of bucks. Cheap compared to killing yourself! Jim

LANDING GEAR STURT O-RINGS… (MAY 03)
From: MarkH85@aol.com
Subject: Re: May #1 GTS Internet Update
On the gear, I wouldn’t cut another oring grove on the inside of the gear bushing. The additional o-ring would cause a great deal of sticktion and the gear will be way too stiff. As Monty said there would be no lubrication to the o-ring and would probably not last very long. — Mark

A VALVE BY ANY OTHER NAME… (AUG 03)
Subj: Shrouder Valve
From: Goody Goodrich <ogoodyg@netex.quik.com>
Jim; The Shrouder {spelling} valve on my right gear is leaking. I have had it out 3 times and cannot get it to stop leaking when I add 5606 and Nitigen. What do I use on the threads ????? It doesn’t look like there should be an O ring or gasket on it , so Now I don’t know what to do – – -help!!!! Goody

Goody, it’s a Shraeder valve. I am at home so I’m just working from memory. As I recall, that air valve has a pipe thread. (tapered thread) True Shraeder Valves have a straight thread and require an “O” ring. If I’m right on the tapered thread, you can take a 1/8″ pipe tap and clean up the threads. When assembling, if you are having leak problems you can coat the threads with Aviation Permatex or Teflon tape. — Jim

THE LEAK THAT JUST WON’T GO AWAY… (AUG 03)
Subj: Gear
From: Goody Goodrich <ogoodyg@netex.quik.com>
Jim; Still working on the leak in my right gear. I need a Stainless Steel Barrel for my ELI gear. Do you happen to know where one would be available??? What are they worth and/or what do they sell for – – – I will be sitting down!!!! Thanks Goody

Goody
Do you mean the chrome strut tube? What is wrong with yours? If the chrome is scratched or damaged it can be rechromed. There is an outfit that advertises in Trade-A-Plane, I think they are in Alabama. They furnish the necessary FAA paperwork also. I don’t know of any serviceable used ones around. Maybe someone will read this and contact you. — Jim

THE LEAK THAT JUST WON’T GO AWAY PART II… (AUG 03)
Subj: Gear
From: Goody Goodrich <ogoodyg@netex.quik.com>
Jim; That is the piece that I am referring to – – sorry I don”t always know the right terminology to use. Mine has a leak around the shaft the runs through it for the bolt. We have soldered and also brazed it, but still have a leak I am open to all /any suggestion that anyone has!!!! Thanks again–

Goody
I knew a guy who found a grade of Lock-Tite that was liquid but set up very hard within 24 hours. He put some in the ELI strut and let it sit for a day. After he serviced it, no more leak. — Jim
PS… I think they rigged up an old inner tube to the strut and inflated it with the air valve to keep pressure on the Lock-Tite while it was setting up.

THE LEAK THAT JUST WON’T GO AWAY PART III… (AUG 03)
Subj: Gear
From: Goody Goodrich <ogoodyg@netex.quik.com>
Jim” Would like to try the Lock-Tite. Do you know which number he used. Some is for threads, which will turn with a wrench and others dry much harder. Also, I understand there is also a Hydraulic Lock-Tite. Would that be the one he used , since it will be in Hyd. fluid… Any help is appreciated….. Thanks

Goody
No, I don’t know which number Locktite he used, presuming Denis runs this in the newsletter maybe someone will make a recommendation. — Jim

SEALING A STRUT… (SEPT 03)
From: Jim Letourneau <jim.letourneau@spacestar.net>
On another topic, in the Swift e-news, there was a question about sealing a strut with loc-tite. I did mine awhile back using number 290, “for assembled parts”. I used a bicycle inner tube clamped over the strut to pressurize the inside. I filled the tube about half full of solvent that would cut the 5606, then clamped the inner tube over the top of the strut and put as much air as I dared and kept it that way for a few days adding air as needed and watching for solvent streaks, of which I never did see any. I cleaned out the solvent and left it for a couple of days to be sure that it was dry. Then poured in the Loc-tite 290 and repressurized for a couple more days. Then washed out the inside and reassembled the strut. This was the second attempt to seal the strut and so far it’s worked for about two years with no signs of leaking. I think that the air pressure is the key. The first time I did the same things without the air pressure and it worked for a short time and then started to leak again. — Jim Letourneau N2424B

ELI STRUT SERVICE INFORMATION… (OCT 03)
Subj: ELI Strut Questions
From: Henry Dittmer <milehighdittmers@comcast.net>
Jim,
So into phase 2 of getting N3741K flying. I’ve read through the ELI Strut information but still have a few of questions.
1) Where in the manuals (I bought the set) do I find service information for this strut?
2) In particular, how much 5606 do I put in?
3) Mark told me about a method of blowing in the fluid as you air the strut. Sounded like a dandy idea since it appears you’d only have to break the strut and the fork, drop it out, service the o-ring, re-insert and fill (i.e. no dropping of the whole gear assembly). Do you know how he made that tool?
Thanks,
Henry Dittmer

Henry
Read the information available on the “Monty The Answer Man” archive on the Swift site. I’m not sure what the quantity is, about a cupful. We have used an old Swift brake reservoir in line with air valves and a hose to blow 5606 in with the air. — Jim

ANOTHER LANDING GEAR SUCCESS STORY, THANKS TO MONTY… (FEB 04)
Subj: landing gear
From: Niel Kardos <nmkden@aol.com>
Dear Monty, During the overhaul of Adel landing gear I came across the following: Replaced the strut tube, resealed the bronze bushing, installed new trunnion tube and bushings. When I applied grease to the new tube/bushings via the zerk fitting on the trunnion yoke, the steel sleeve which is bolted to the trunnion yoke slid out of the yoke 1/4 inch. Your advice that this should not happen was confirmed when I separated the yoke from the sleeve and discovered that someone over 30 years ago had opened up the bolt holes into slots…. The extra hydraulic pressure needed to force grease into the new closer tolerance spaces between the bushings and the trunnion tube was enough to dislodge the sleeve from the yoke. Mark Holliday was able to fix me up with an intact serviceable sleeve, so my strut is back together correctly, and installed on the airplane. I flew for years with that funky strut, held together by nothing but “interference fit”. I dunno. Thanks for your help and advice. Best personal wishes. Neil Kardos

RUSTED AND PITTED GEAR STRUT… (MAY 04)
Subj: gear legs
From: Travis Foss <duster4@earthlink.net>
Hi Monty,
I have some rust and pitting on one of my gear struts and was talked out of re-chroming. I have an original GC-1A leg with the reservoir at the top that is in great shape. My question is, are the original struts and Adel struts the same/interchangeable? Thank you for your time. Regards, Travis Foss
P.S. I have attached a photo of a crack I found on the rear bulkhead of the gear box.

Travis
Parts, like the chrome strut are not interchangeable between the two gears. The complete landing gear assemblies are interchangeable. Are you restoring N80529 to original with the C-85? The info I had on the airplane was that it was getting a 150 Lycoming. The original GC-1A landing gear is not eligible for use on any thing other than a GC-1A. See SB #27. The early gears had much better chrome (thicker) than the Adel landing gears. The Adel gears just had just a flash coat of chrome. The early strut could be safely rechromed by an FAA approved shop. The early strut comes apart much easier than the Adel, and just use heat to get the fork off the strut tube. From the photo, it looks like that crack has been welded. Is that right? The gearbox bulkhead is a non-weldable alloy, so that is not a legal way to repair it. A repair doubler with flush rivets on the gear side can be installed per AC 43.13-1B. — Jim

VASELINE, IT’S JUST NOT FOR BABIES ANYMORE…(JUNE 04)
Subj: struts and gear doors
From: ccoombs@bellsouth.net
Monty,
A few newsletters ago I read a letter inquiring about the P-51 gear doors contacting the tires when the strut is flat. I encountered this as well on N853C. Luckily it was in my hangar on preflight. The strut just went flat while I was attempting to move it out of the hanger for a flight. I immediately noticed that the left gear door, forward stiffener was in direct contact with the main wheel. Had this happened on landing, it would have done one of two things. 1. Rip the door off it’s hinges, or 2. Cut the tire and consequently lock the wheel up enough to cause a ground loop, in which case, the gear door being torn up would only be a minor inconvenience as compared to the consequences of a ground loop. Upon further investigation, I noticed the right gear door, forward stiffener had a cutout that accommodated the curvature of the tire in it. Apparently a previous owner had taken care of this problem on the right gear only. I immediately made the modification to the left gear door and now I can rest easier. As a suggestion, it’s always a good idea to make sure your struts are serviced properly as this is the best way to keep unexpected things from happening. But next time you have your swift on Jacks, it might be a good idea to check clearances with the struts fully compressed. Remember Murphy’s law always prevails! Regards, Cody Coombs

Cody
This is mainly a concern for those with ELI landing gear. As I have mentioned before, keep the “O” ring lubricated by applying a little Vaseline to the strut cylinder often. This will keep the strut inflated for years. — Jim

LANDING GEAR STRUT STUFF FROM DOC… (JULY 04)
From: “Doc Moore” <darladoc@sport.rr.com>
Subject: Eli Gear
Jim: Want to update some info for the archives on tips for servicing ELI struts. As you are aware from my previous email, the STC’ed gear door linkage was originally done for the Adel strut. Because of the springs in the Adel gear the strut won’t collapse in the event of a leak. The ELI gear will. When this happens, the door, if set up per the STC, will be pulled into the tire causing a significant problem. I am presently addressing this issue and once I’ve figured out new geometry I will send an update along with pictures. When I disassembled my strut it was void of fluid and the O ring had rolled and was cut like a spiral cut ham. I never saw any fluid leak so I have no idea where it went. In addition, when the strut collapsed it bent the door and ruined a tire. It also bent the linkage and the torque link settled on the stop that mounts on the torque link damaging it. On examination I found that the edges of the groove for the O ring were as sharp as a razor blade. The top of the bottom half of the strut was also very sharp. I worked on these items for a good while with fine emery cloth and got them smoothed out. After reading all I could on the archives and talking to experienced Swifters I generously lubricated a new O ring (AN6227B-35 from Aircraft Spruce) and installed it in the groove. I then lubricated the strut and, at the great suggestion of Ed Lloyd, obtained some .0003 steel shim stock and cut it so it would just wrap around the strut. I then put it up inside of the O ring and then fitted the lower half into the upper half. It went in very easily and the shim stock was no trouble to remove. Be sure to lube the shim stock up with Vaseline, too. This helps both in pushing the strut past the O ring and in getting the shim stock out after the strut is past the O ring. Concerning how to put in the hydraulic fluid….. the first thing I’d tell you is that if your upper and lower plugs are not leaking don’t remove them. Just before you are ready to fit the two halves together fill the bottom half of the strut to about 1/2″ from the top of the hole in it. This will be right at 3 ounces of fluid. Then, holding the bottom half of the strut upright on the floor, work the top half down until it gets past the O ring, then work the shim stock out. (My wife was an able assistant on this job) After you do this you can move the strut around in a gentle arc as you try to get the upper damper tube into the lower hole. All of this needs to be done with the strut completely out of the airplane because you’ll never get the damper tube in with the unit in the plane. You’ll meet resistance from trapped air when doing this but its no problem to overcome the pressure. Once you get it in install your torque link to hold it and you’re ready to re-install. You can air the strut with Nitrogen once its re-installed. I’ve found about 190lbs of regulated air with the strut fully extended will give you the recommended 3.5″ of exposed strut. Before re-assembly of the strut halves, I also took two of the above referenced O rings and put them over the lower strut to act as a shock if the strut collapses again. Two of them keep the stop from bottoming out and getting damaged on the torque link. Well, that brings you up to date on my adventure so far. Stay tuned for the continuation as I solve the problem of the linkage geometry.  —  Doc Moore

ELI GEAR VALVE STEM LEAKING AROUND THE THREADS…(AUG 04)
From: Ron Williamson <rwwilliamson@earthlink.net>
Subject: ELI gear question
Hi Jim,
The prior e-mail traffic reminded me that I need an answer from you also. The valve stem for the ELI gear is threaded into a counterbore that’s located on the big casting that holds the axle and wheel assembly. One of mine is leaking around the threads. Since there’s pressure in the gear, I have to deflate it before I can see what the sealing mechanism is. It would be nice to know in advance. So, here’s the question. Is the valve stem insert thread a straight or taper? If straight, is there some kind of o-ring seal where it snugs down against the gear casting? If there’s an o-ring, do you know the size? I’ve misplaced my Commings book, so I don’t know if that information is in it or not. I’ve searched through all the stuff I have here at home and have no detail info for the ELI gear, but I recall a sheet that showed the various bits and pieces. Although, my memory is somewhat fuzzy as it’s been a while since I worked on the gear. Thanks in advance, Ron

Ron
The valve is not a true Shraeder valve — it is a 1/8″ pipe air valve. (tapered thread) Maybe just tightening it will stop the leak. If not, after removing it and losing the air and fluid, examine the threads. If necessary, use a 1/8″ pipe tap to clean them up. Reinstall the valve using some form of LocTite. I don’t think the Commings book has anything on the ELI gear. I presume you are familiar with servicing the ELI gear. Nice to hear from you. — Jim
PS Thanks for the reply on the Swiftronics question