MAECO Shimmy dampener repair

Harley Kleemann

My shimmy dampener was tired, I found that out when I started getting a slight shimmy when I'd land. Sure enough, the dampener had several spots in the travel where it offered no resistance. I purchased an stc from Knots 2U for a kit that includes the paperwork, a drill bit with a stop collar, a Scotch Brite pad, and a Phillips head 10-32 plug with an O ring on it. Basically, you Scotch Brite the end of the cylinder down to bare metal, center punch the end, and drill a hole in the end of the dampener, Using a 10-32 bottoming tap, you tap the drilled hole, then invert the dampener and plunge all the old fluid out of it. The crap that came out of my dampener was black! After getting all the old fluid out, you refill it with clean 5606 hydraulic fluid. I used a 150cc syringe that fit the drilled and tapped hole, and let it drain in until it took no more fluid. During this procedure, it helps to move the piston rod in and out to help get the air out. Using the Phillips head plug and O ring, I screwed it into the tapped hole after I made sure all air was evacuated. Now the dampener offers excellent resistance, and, no more front wheel shimmy! My local FBO A&P guys signed off the logbook and filled out the 337 form for the FAA. Keep in mind, this kit will only work if the internal valving in the dampener is not kaput! But, the kit at $175 is sure a whole lot less expensive than $1000 for a replacement dampener!

Scott Sherer

Excellent job, Harley. The overhaul kit is only good on MAECO shimmy dampeners. My new Arrow didn't have a MAECO and needed an overhaul, but that's another story. I'm glad it worked out for you!

Harley Kleemann

Scott, what dampener do you have on your Arrow?

Scott Sherer

Hi Harley,
It's an original and when it needs overhaul you have to replace it with a new one for $900. Then you get a MAECO, lol.

Harley Kleemann

I did some checking with Parker Cleveland, a new shimmy dampener for an Arrow is over $1700...yikes!!!

Scott Sherer

Yes indeed

Bduffey

The other thing to look at is the bushings on the steering linkage. It is actually a bit more likely to be the issue than a bad dampener. The good news is that is much less expensive to resolve. I had some shimmy and it just slowly got worse. If you examine the linkage with weight off the nose gear, it is fairly obvious. New bushings and bolts resolved everything back to normal.

Safe flights.