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  Strut Repair & Overhaul Resources




My refurbished Main Gear Strut - Join ABS and see the complete Feb 2015 article HERE


HERE is the Baron Nose Gear IPC Extract


HERE is the Baron Main Gear IPC Extract


HERE is the Bonanza (H35-V35) Main Gear IPC Extract


HERE is the Bonanza (H35-V35) Nose Gear IPC Extract



B55 Nose Gear Trunion Assembly


B55 Nose Gear Trunion Assembly Above Includes:

Brace PN: 45-820096-17

Collar PN: 45-825033

Orifice Tube PN: 36-820021-3

Barrel PN: 35-825195-33

New felt 35-820130-2

New scraper ring MS28776M2-19

New high pressure valve AN809-1

New boss gasket MS28778-5

New top o-ring M25988/1-223

New Barrel middle o-ring M25988/1-224

New grease zerks (Quantity 4) PN: 1792

Add your own Appliance Epoxy Paint job and you'll have a very nice replacement.


Need Strut Seal Repair Kits?

Check Out

Supporting Site Member



Want to take your landing gear struts from this:



To This:




The big bronze bushings PN: 35-820115 are located in the top and bottom of the trunion body. The bushing is #5A HERE for the Bonanza (H35-V35) and part #47 HERE in the Baron Nose Gear IPC Extract.


See my complete article in ABS Magazine February 2015 on my Main Gear Strut rebuild HERE .



CSOB Strut Center O-Ring Removal Tool


Here are some tips dated 5/29/2020, from 1975 F33A Bonanza owner, Shep J., on how he attacked the removal of the MLG bolts during his strut rebuild:

"I was able to get them out with a C-Clamp.

Now that they are out, I compared the upper and lower brace bolts and came up with some interesting food for thought…

They are both 7/16” diameter. The uppers are hex bolts that I measure as being 1 15/32” with a 1” grip. I don’t know what to call the lowers but measure them as being 1 3/8” with a 31/32” grip.

Look at the picture below to see what you get if I add a .063 washer to the upper bolt…same grip, just a hair longer."

Upper Bolts #130909B9, $10.34ea
Lower Bolts #35-815247-15 $231.25ea

Here is more research done by F33A Bonanza owner, Shep J., on the history of the bolt PNs in his 1975 F33A. The following info from Shep is offered for your amusement and entertainment only.

NO APPROVED RECOMMENDATION is to be implied or inferred as relates to your aircraft maintenance. You and your A&P mechanic are responsible for your maintenance choices for your certified aircraft.

"…so I called Mike T. in Lakeway, TX which is just west of Austin. We discussed these bolts at length and he said his 1981 F33A had hex bolts on the lower truss connecting points instead of the ones with the small heads. This explains why the NAS part numbers he came up with were so similar and just a tick different in length and when he put his back together 2 years ago he went back with the replacement hex bolts. So I went around and looked at 5 Bonanza’s on the nearby ramp here at Addison (KADS) and found that 1 of them (a 1979 35 model) also has hex bolts but the other 4 have high dollar lower bolts like mine.

I did some more digging through the IPC’s and found that they started using the MLG with the separate trusses around 1967 but from 1967 to about 1970 they used the same 4 bolts at the upper and lower points then changed to the lowers using the high dollar bolts from then on. The picture below shows the design difference made around 1967.

From 67 to 70 they give the same part number for all four bolts… NAS464P7LA16/M which is 7/16-20, 1-29/64", 1" grip and now superseded by 130909B9 which are about $10 each.

In 1970 the lower bolts were changed to the current one which has the small head and costs over $235ea. Did they change it because of a clearance issue? I’ve studied it and don’t see any. Is the current one a higher strength bolt despite having the smaller head? I have no way of determining that.

If your plane was in the 1967-1970 range the IPC calls for the same four $10 dollar bolts upper and lower on what in every other way appears to be the same landing gear. I did some spot checking and all the part numbers on the trusses are the same from before 1970 and after. The top brace part number is 35-815251-1 but is superseded by 35-815251-3 in 1970 yet the top bolt stays the same.

It is proper and legal to use the same 4 bolts if your plane was made from 67-70 at the upper and lower attach points. Is it wrong to substitute the same bolts for the lowers from 70 and up? I know the answer already but have to wonder why not?

I have since found two post 1970 planes with hex bolts at the lower truss attach points…a 1979 35 and a 1981 F33A (see image below). Did someone go through this process in the past, came up with the same info and decided to use the upper bolts on the lowers?"

1981 F33A Hex Head Strut Bolts Observed on Ramp


Don't be the guy who haphazardly installs the main strut top snap ring in this manner. This is a disaster just waiting to happen!

MLG Strut Watchout for Late Model B58 SN: ~TH-1300+

There are community reports of internal corrosion failures of B58 MLG struts. A 2001 B58 owner, Kevin M., reports that his gear would not retract after liftoff. After troubleshooting he and his mechanic found that there was internal strut corrosion so bad that it prevented the strut from fully extending, thereby leaving the squat switch activated, which prevented retraction as it is designed to do.

Delta Strut reports that after about SN: TH-1300 the strut design and manufacturing was changed

and subsequent struts are more susceptible to this internal corrosion. There is no seal at the bottom, only a scraper ring. When the felt runs out of it's initial dose of engine oil, water and moisture creep in and begins destroying the internal housing body.

This is an insidious failure which can render the strut wall thickness extremely thin without visible evidence of impending doom.

Paul B. suggests pulling the felt every few years and installing a new freshly oiled felt could possibly be the best prevention for this strut design.

A new strut from Textron for these models is reported to be $8,200 .

Are your struts on their last "legs"? Tired of servicing them with nitrogen and 5606?


Beech Owner Dr. Dave Rogers offers this pirep on his A-36, E33A strut repair/rebuild:


"A-36 nose gear strut and the left main gear strut on the E33A repaired by Eric Massey at Safe Flight (410-643-7728) in Stevensville, MD (W29).  He did a good job at a reasonable price."



DIY Nose Gear Strut Servicing Tips from Beech Expert Paul M.


(as published in Beech Talk thread HERE)


1). Be sure you check the end play on the strut ass'y where it bolts to the airframe. Often those shims are left out or its never checked after years of service. I think max play is .015 (check the MM to be sure) and you use up to two 100951S016YP washers per side to shim the play out of it.

2). Replace the laminated shim that goes under the top "cap", peeling each layer off until it fits freely. See MM. Those shims don't last that long and should be replaced and the strut/top cap play eliminated whenever the strut is disassembled.

3). If the felt pad is in good shape, there is no need to replace it. If you do replace it, you may need to trim it. Also, do not "over-soak" it in SAE 10 oil or it will swell up so much you'll never get the piston into the strut.

4). Get a hose that will fit over the Schrader valve threads snug enough, and dip the other end into a gallon jug half-full of 5606 for the servicing part. That's really the best and quickest way to service a newly OH'd (dry) strut. Have your assistant hold the jug while you actuate the strut slowly, stop to stop, until its sufficiently filled. Sufficiently filled on the later model nose gear is the piston fully compressed to the stop after 3-5 full travels of the strut. Earlier models called for compressing the strut to within a 1/2 or 1/4 in. of fully compressed before calling it good, IIRC. Remove the hose while the strut is compressed. Then you can relax. Put the valve core back in and put shop air* in the strut until you can get the plane on the ground and service it the rest of the way with nitrogen.

5). Make sure you don't accidently bolt the steering "collar" to the strut with the zerk on it pointing up, as you won't be able to grease it. It can swivel 180 degrees while its disassembled without you noticing it. Seems like I've seen that a lot lately on some new customer's airplanes. Make sure that steering stop "cone" rolls freely on the end of that bolt, too.


*CSOB1 note: Some "shop air" can be laden with moisture (which can corrode the insides of the strut), so be careful if you choose shop air.



Here is another piece of guidance for nose strut rebuilding from Beech Talker Larry M.


With the plane on jacks, remove the nose gear. When you disconnect the steering yoke, careful for the tiny spacing bushings that fall out, get lost. These are very important. Carefully bleed pressure from the Schrader valve, remove the valve, replace the O ring under it.

Drain 5606 fluid. Remove tire and wheel from axle. Remove lock ring at top. Disconnect NG torque knee. Be systematic in disassembly, carefully store parts to help you with reassembly. When cylinder is open reach in lower portion and remove oil soaked felt, and place in solvent to clean. Have your new O rings (Performance Aero) ready, and greased with #5. Make yourself an O ring pick from a brazing rod, sharpened on the ends. Bend one end at a 45 degree angle, the other about 120 degrees. Shine your light into the tube, locate the old O ring, stab it with your pick, and work it out of the groove. Be prepared with two 3/4" dowels, about 2' long. Place the new O ring on one dowel, insert into tube, from the other end, insert other dowel. Now you can work the new O ring into the groove, and push it fully into place.


Clean and examine scraper, install other easy O ring, wash the felt and re oil it. Your maintenance manual will give you wear allowances for you to measure with a micrometer. If you have no excessive wear, you can reassemble. Reinstall, add new 5606 to a collapsed strut, work it up and down for bubble removal, check level to full with a 1/4" block at bottom. New valve core, inflate with nitrogen to about 125 lbs, adjust later to proper height as shown on your strut decal.


While you are in there, check the magnesium strut delta for corrosion. Water gets into the vents in the front, and bi-metal action takes place. Some of those parts are dissolved like an AlkaSeltzer tablet. Prevent that by making a curved aluminum cover for the vents in front. ABS has details.


Blackwell Aviation is a supporting site sponsor and states that they specialize in nose and main landing gear restoration for the full line of Beech piston aircraft.

Another popular strut repair/rebuilding source is Delta Strut, the company previously owned by Arky Foulks and then Lawson Barber.


Delta Strut is now owned by John & Tracy Koester.


NEWS FLASH 1/1/2018: Delta Strut began 30 plus years ago in Stockton, California near the Sacramento-San Joaquin River Delta, and so the name "Delta Strut". The company was purchased in the 1990's by Arky Foulks and moved to Mesa, Arizona. In 2007 Lawson Barber bought the business from Arky and moved it back to Madera, California. A few years later Lawson moved the operation to the Fresno area where it is located today.  On January 1, 2018, John and Tracy Koester became the new owners of Delta Strut and run it out of Clovis, California 93619. Lawson Barber will remain in an advisory role and will continue to share his 50 years of Beechcraft experience with us all.


559-441-1316 (Land Line)



Be careful, if you break this snap ring that lives on the end of the shock tube, it is rumored to be about $200 from Beech.





Here is a find by BeechTalker John K. Can you tell the difference between these two PN: 504270 strut seal parts? I didn't think so!



The one on the left is a nose strut shaft seal from Beechcraft at >$20 and the one on the right is sourced HERE at $9 or HERE for ~$6.50!




The main strut lower shaft seal is PN: 504271 and is available HERE for ~$10


The nose gear strut scraper seal is PN: MS28776M2-19 or NSN: 5330-00-517-0388




Need high pressure valve parts? AN809-1 is what is used. Check these folks out:






Click HERE for a catalog of Standard & Custom High Pressure Fill Valves



Here are some pictures (click on them to get full size) of the valve core body area and why you really should use the specified "BOSS" gasket PN: MS28778-5 for the sealing of the valve core body to the top strut tube. I found crush washers in use on a pair of serviceable main struts I was refurbishing to replace my 50 year old main gear legs.

It is much simpler if you can, to find a younger pair of "legs" and refurbish them then, having them at the ready, insert them at annual without removing the supporting structure from the airframe. Also less chance of gear mis-rigging, IMHO.


The top tube O-ring for the later model Bonanza & Baron Struts in black nitrile rubber is MS28775-328, in flurosilicone blue it is M25988/1-328. The barrel center o-ring in black nitrile rubber is MS28775-138, in flurosilicone blue it is M25988/1-138.


Sources for nitrile and flurosilicone o-rings include Aircraft Spruce and O-Rings Inc..





Below is the nose gear valve core body showing that it too uses PN: 28778-5 "boss" gasket for sealing.



Over many years or in fact decades, these gaskets are prone to wear and can be the source of frustrating leaks. So if/when you tackle this job, do it right and refurb all the problem areas so you can get another 40-50 years out of them!





See the Bonanza 33 Series Landing Gear IPC Extract HERE




Here is a picture of the parts list for a Baron 55 main strut rebuild. Caveat: Check your parts catalog to be sure this works for your SN airframe!




Here are pictures of Nose and Main strut seal repair kits that have been seen on eBay. Do your research in your parts catalog to be sure you get the proper pieces for your specific SN!


Main Strut Kit


Nose Strut Kit



Got Leaking struts? Well here is a pirep from Debonair Owner and Beech parts maven Kevin O.:


"When I bought my Deb15 years ago , both my main gear were leaking. I used a mixture of 50/50 trans stop leak and 5606 just to get me to the next annual.


WELL--never did leak again. I have to add a little nitrogen about once a year---and a little fluid about every 3 to 4 years. My struts have never been rebuilt ( 1960 Debonair)


I do have a new set of mains still in the wood beech crate that were built in 1961---when the ones on my plane start giving me trouble--will put new seals in the new set and put them on.


Transmission stop leak is less than $5.00 a bottle---Granville Strut Seal is 5-6X$! Same functionality--both soften the seals and cause them to swell just a little."





Here is a picture of a typical o-ring failure that causes the strut to deflate or lose fluid. On the left you can see the deformed edge, on the right a new o-ring.






Landing Gear Scissor Grease Zerk PNs & CSOB Sources



More Zerk info HERE


PN: 1729 (AKA 3016) 




PN: MS15002-1 or AS15002-1-P or 1792B 



Are you shocked by the high cost ($23) of Strut "Felt Wiper" from HBC?



Main Strut Felt Measured: 6 1/4" x 5 5/8" x 1/4" thick


Felt Lives in HERE


Pull old felt out like THIS


Here is a find from Beech Lister Bob N. to solve that dilemma in CSOB style:


From W.W Grainger :


Felt Sheet, F3,1/4 In Thick,12 x 12 In

Item # 2FHG2, $7.24



General Purpose, Wool Felt, Backing Type Plain

Thickness 1/4 In, Width 12 In, Length 12 In, F3 Grade, Gray Color, Density 4 Lbs/Sq Yd




Felt Sheet, F1,1/4 In Thick,12 x 12 In

Item # 2DAH9, $11.62 ea.




General Purpose, Wool Felt, Backing Type Plain

Thickness 1/4 In, Width 12 In, Length 12 In, F1 Grade, Off White Color, Density 4 Lbs/Sq Yd.


F1 and F3 refer to the SAE grade, F1 is the highest. Both are indicated for wiping applications.


They also have it in 24"x24" sheets.



Nose Felt PN: 35-820130-2




Legacy Nose Wheel Grease Felts are Retired


Speaking of Felts, here is a discovery that the legacy 5 x 5 nose gear grease felts have been discontinued in favor of a molded grease seal.



WOW, how long did it take to get out of 1940's grease sealing technology????


HERE is the Parker Reference Memo (PRM97) outlining the change.



Sanded with 220 grit and ready for Rust-Oleum Appliance Epoxy!





Main Gear Scissor Linkage



Many airframes are equipped with the lower scissor zerks in a difficult to grease upward facing position. Whose idea was that? Or was this a Beech shop floor Boo Boo? Well, those zerks are a PITA to get a grease tip on unless it's annual time and you have the plane jacked up and the outer gear door linkage detached. BUT, alas, we have found lower scissor linkages with the zerks facing downward in a much easier to grease position in PN: 36-810016-5 as seen below. Possibly easily sourced at eBay if your zerks are really that bothersome to you.




OK, since you hung in this far on the strut rebuild page, you must really be interested in this topic. As a reward, HERE is the ABS Article Extract and high resolution Figure links!


Figure1   Figure2   Figure3   Figure4   Figure5   Figure6   Figure7   Figure8   Figure9   Figure10


Figure11   Figure12   Figure13   Figure14   Figure15   Figure16


If you've found this content useful, even though you're a card-carrying CSOB, please consider a secure PayPal donation by clicking the "Donate" button to defray some of my expenses.


Easy N2 Filling Hack To Balance Main Strut Heights


Aerostar Shop Manual Diagram

After years of bouncing back and forth with the N2 tank between the two main struts of my B55 to achieve an equal strut height on each side, my IA came up with this simple but effective hack to equalize the strut heights.

It simply involves making a "T" connection off the N2 tank to connect to both struts at the same time. It works great! We simply jack the plane (using a tail stand obviously) to extend the struts to max extension, connect the N2 lines to the top schrader valve, then open the valve on the tank and adjust your pressure accordingly. We like the Gooseneck filling connector PN: SK2043C

Bonanza owners/visitors are encouraged to   me with the pressure they use and chrome height results they achieve for their model.

We use a regulator to precisely meter the pressure of the >2000psi N2 tank and hope that you will too.

My full-fuel B55 takes 370 psi to create roughly 3" of chrome showing on the strut when the full fuel weight is on the wheels. Your height preferences may vary, but at least you have a psi benchmark to work from.

The B55 nose is reported to need ~200 psi when on jacks to create 3" of chrome showing. I had my plane off the jacks just after annual and the nose was at about 2.25" of chrome showing. Rather than jack the plane up all over again, I decided to try adding N2 with weight on the nose. I installed the above goose neck fitting to the strut and set my regulator to about 250 psi then went to the tail and rocked the tail up and down a little and was able to achieve the 3" of chrome showing.

PS: Meyer's Jacks are the best, however, they are extremely expensive as jacks go. I inherited the pair seen below. They are Model A5 and I recently (3 December 2023) rebuilt them with the excellent Meyer rebuild kit PN: K-150A.

Details to build your own N2 filling rig can be seen HERE.

Below are pics of the "T" rig that I use and my results


1994 A36 owner, Jose R.. reports inflating his struts (with wheels off the floor) to 215-220psi.

1972 F33A owner, Steve B., reports inflating his main struts to 150psi and getting 3" of chrome showing when full fuel weight on wheels.


If you've found this content useful, even though you're a card-carrying CSOB, please consider a secure PayPal donation by clicking the "Donate" button to defray some of my expenses.