Hi Robert;
It’s my experience that nose gear shimmy is not related to the shimmy dampner.
My first suggestion is to balance the wheel/ tire assembly. If your mechanic doesn’t have a balancing tool, you can try taking the tire wheel assembly to a motorcycle shop if there’s on nearby. If you’re not near someone who can balance the assembly, you can do it the “bush” mechanic way, which is to completely degrease both wheel bearings and the races. Then mount the tire/wheel on the airplane. Since there’s no drag on the wheel/bearing the heavy spot on the assembly will end up at the bottom. Install balance weights (get them at the auto parts store) until the assembly does not stop in the same place every time.
If you find it hard to balance, make sure that the red dot on the tire is aligned with the filler valve stem or silver spot on the tube.
If the balance is good, then I would look very closely at the nose gear torque links. Look closely for cracks. Check for slop in the torque links by installing the tow bar, and watching the lower, middle and upper connections of the torque links as a helper slowly moves the tow bar back and forth. There should be zero “slop” or play in the three connections. If there’s wear, the torque links can be rebuilt by installing new bolts and bushings. Make sure the proper bolts are installed.
I have attached a page out of the Tomahawk service manual pointing out the need to inspect for cracks in the nose gear housing.
If you can’t find anything else, I would take a look there.
Happy Flying,
Steve
