Because Owning And Flying Your Beechcraft Can Be Done Safely AND For Less Money!
  Shimmy Damper O-Ring R&R




So, when you do the little safety wire check specified in your maintenance manual for the fluid level of your shimmy damper you get something in excess of 2.375" to 2.75"?


By the way a measurement of 2.125" is supposed to be full (per my Baron maintenance manual anyway).


Or, you see this little puddle of 5606 hydraulic fluid on the floor under the rear shaft of your shimmy damper?


This means you'll need to add fluid and/or overhaul all the o-rings in the unit.


HERE is a link to a very helpful pdf (developed by Elliott Schiffman and Denis King) that will take you and your mechanic step-by-step through the process. Click HERE for the presentation that has been given several times at the ABS tent during Oshkosh.


Here is a sketch of a shimmy damper fluid level measuring tool posted by Larry M. on Beech Talk



Here is a list of all the o-rings you will need for the project:


2 each AN6227-1 (MS28775-006)

2 each AN6227-7 (MS28775-012)

4 each AN6227-13 (MS28775-115)

2 each Beech P/N 1009432E316G Springs

1 each AN960-3 Washer

1 AN380-3-2 cotter pin (MS24665-281)

1 6-32 threaded rod


O-Ring Reference Guide PDF HERE


Shimmy Damper by Larry Matlock (11/2017)

I am going to tell you a story about an unusual job, overhauling the shimmy dampener on the V35B. It is OK to call it a damper, a dampner, or a dampener, as it dampens the gyrations of your nose gear.


The first clue there might be trouble was attempting to measure the 5606 in the unit, and the cotter pin was closed, not opened with an awl so the measuring wire goes in. Removing the innards, done many times before, no shooting springs and tiny washer... in fact no springs, no washer, no plungers, and no fluid of any kind.


I had the parts on hand, purchased from Performance Aero, and had to buy about 200 AN 960-3 washers, just to get one + a spare. ( if you need some..) Inserting the brass bore brush, I found it would only go halfway through, the clevis side had a stuck floating piston and spring. Rusted solid! After a soak of Hoppe's #9, a tip from Bob Butt, I was finally able to knock out this rusty debris with a long drift punch. I was left with about 2.5" of rusted bore way back in the clevis end.


I plugged the hole with a shaped chopstick, and with an eyedropper, filled the bore halfway with Phosphoric acid, this one called "Rust Mort" by Loctite. After a 15 minute soak, I was able to get the brass brush the full distance, but a look inside showed the damage from the rusting spring. I shaped a bamboo chopstick on my drill press, using two files, to just fit the bore, fitted this rod in my electric drill, soaked the bamboo with MMO, and dusted it with diamond dust polishing compound.


About 5 minutes later, I had a shiny polished bore, that the floating pistons were happy with. Reassembled with new O rings, the dampener worked like new, very hard to push and pull, as the 5606 moved from one side to the other. A tip is to pull the 6/32 all thread out the clevis side as far as possible against the spring, and use a nut to hold it while filling.


Filling the back end, where the cotter pin goes was done with an eyedropper, then a special tool I devised consisted of a 1/4" OD tube, similar to a old car radio antenna, with a slot 1/2" deep to clear the cotter pin, and a stiff wire to line up the spring and keep the tiny AN-960-3 washer from shooting away. The center bore was filled, safetyd, and re installed. 


Adding a squirt of LPS3 in each end of the dampener, to lube and corrosion proof the springs is the final thing to do prior to installation. Also, a little of the same on the open plunger shaft will be welcomed by the O-rings. Mike T. says he greases those springs prior to the installation. Another good idea!


The moral of this story is to never wash your airplane with soap and water and a hose... and heaven forbid a pressure washer. Be a great Beechcraft owner and hand wash your bird with an old cotton towel and dry with a chamois. When spraying water all over the place, the water will go inside your shimmy dampener clevis end, and it can't get out, until you have the rusted unit from hell I just described above. Wash N Wax all, or a brush with avgas to clean the nose gear.


Keep the water away from your shimmy damper!



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