LANDING GEAR STRUTS #3

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