Shimmy Strut
 

Any easy way to service the nose wheel shimmy strut? Very difficult location for my hands to access.

Usaully if it needs servicing, a seal has gone out, so it would need to be removed, repaired, serviced and reinstalled anyway.

the only real safe way is take the weight off the nose gear, and someone with a somewhat skinny enough arm, reach up through the inspection hole to gain access to the servicing valve...I think the book calls out for between 35 and 40 pounds....I typically put enough air into it to where the scissors look like a strecthed out "V"...if you put too much air in the strut, you will not be able to steer

Wes Grady
KCCB hangar 208

We used to put the nose on a jack and lift clear of the ground, chock behind both main wheels and put the u/c lever up and pump the gear until the nose gear unlocks. The shimmy damper is easy to get to then. The mains cannot unlock and go up due to the weight of the airplane.

Pete

Are we talking shimmy dampner or nose strut here? The dampner is on the top of the gear.

I asked about the nose wheel shimmy...sorry for any confusion.

Before you tackle the shimmy dampner, you need to do a few basic troubleshooting items first:

• Make sure that the nose tire is inflated to specs.
• Make sure that the nose wheel bearings are no defective or the axle bolt is too loosed.
• Make sure that the nose tire is within balance.
• Make sure that the nose gear torque links do not have excessive play.
• Make sure that you don't have a warped main gear brake disc.

This will eliminate some of the more common causes of nose gear shimmy before you tackle the dampner. Usually the Skymaster shimmy dampners work for many years without any difficulty.

However, I have found an easier indicator that it is the dampner: if it happens only when the dampner is hot. I've had to overhaul the dampner once on each of my two Skymasters and each time there was no shimmy on the first takeoff of the day (especially if it's a cool morning) and shimmy when you landed on a hot day (I'm in Miami) or if you took off soon after a hot landing (remember that the dampner is close to the front engine). One other thing: if the housing is sound, your A&P can rebuild it using the seals shown in the parts catalog.

Ernie

You can also connect your tow bar and turn the nose gear left and right, if the dampener is low on fluid it will make a squirting sound.
Kim

I had this problem about a year ago and my mechanic convinced me to change the front tire first and if that didn't work, he'd pay for it. It worked! The old tire looked OK but his knowledge of the problem told him that he had worked on lots of shimmy dampners first then find out all that was needed was a new tire!

Replacing the shimmy dampener
 

Well after researching the issue here and talking to a number of folks that basically shrugged their shoulders the most useful blog was the suggestion to raise the nose gear.. a bit. So today we jacked the aircraft (we had to anyway for the annual inspection) put the gear handle up with the circuit breaker pulled and then used the breaker to raise the nosewheel to about a 45 degree angle I had already removed the front wheel to balance it Sho nuff this gives you room to get your hand and side cutters up to remove the cotter keys and then the nuts. Front bolt no problem to remove from within the engine compartment. The rear bolt was tougher. we turned the wheel all the way to the left (after disengaging the centering mechanism) and managed to raise the bolt just enough to clear the dampener ear. Now to rebuild the dampener, put it back in and enjoy installing new cotter pins!!! Easy huh??
Peter

Balancing the tire assembly dynamically helps a lot also. I have an older Snap On car tire balancer that I modified, works great. Instructions are on the web. Do a search of balance aircraft tires.

Dan