Tailwheel Shimmy

Robert Eilers · Post by **Robert Eilers** » Sun May 20, 2007 3:30 am

Thanks Mike - but, part of the mystery I am dealing with is that I did replace the main leaf spring. The tailwheel geometry seems to be OK. I think I am just going to have to rebuild the tailwheel.

Mike Smith · Post by **Mike Smith** » Sun May 20, 2007 3:19 pm

OK, good luck. I know how frustrating a continuing item can be when multiple "fixes" don't seem to work. Once you get it done it'll be great to have it airborne for the summer fun flying!!

Post by **Bruce Fenstermacher** » Sun May 20, 2007 3:47 pm

Robert

You should not be able to wiggle the fork as I think you are describing.

At one time I went through some of the same things you are. No shimmy but the wheel just wouldn't steer as good as other 170s I've flown. I trying everything. disassembly, cleaning, more grease, less tightening, more tightening. Nothing made a change.

At the time new 3200s cost at outrages $475. No way I was buying one. About the time I was about to give up they jumped to $750 and my stubbornness against buying one was renewed.

Then one day I mentioned the problem to my friend and what I'd done about it. I mentioned that when I remove the king pin it looks fine. He looked at me as said "The king pin comes out of yours?"

Well it's not suppose to.

So I had a machinist friend knurl the top of the king pin and press fit it back into the top housing. My machinist friend noted that the pin was as straight as he could make it referencing any of the other surfaces because none of them where straight anymore. The didn't look bad, OK not that bad. Basically the tail wheel was shot. I lucked out "I think" and bought a rebuilt one with a new fork from ebay for what I could have bought a new one had I just done that when I started.

So my advise to you is first find a good 3200 to compare yours to. Your problem might be obvious as mine became. Second, as simple as these things are they do rely on a precision fit of it's parts. Perhaps yours is shot and someone loosened it just so it would swivel but that is just to loose to stop the shimmy. Or you don't realize how tight the king pin needs to be.

Post by **GAHorn** » Mon May 21, 2007 3:53 am

I agree. If you mean by "looseness"...that the fork will move laterally or axially...then it's worn out and needs overhaul. There should be virtually no play in those directions.