The International Cessna^® 170 Association

Anyone else experiencing the bolt turning after multiple landings? This bolt is one I purchased when they first became available. I have added one or two washers based on previous posts to make sure the nut isn't bottoming out on the threads. I use 60 ft lbs torque and continue to see the ring has turned as if loosening. Only turns maybe 1/8th of a turn, if that much, before I retorque it. Suggestions?

Since you made sure the bolt wasn't bottoming out on the threads, keep checking and retorquing it.

It's coming loose because the fit between the main spring, the tailwheel adapter and the tailwheel has slop and it will twist no matter how tight you make it. And the twisting action loosens the nut. The bolt is not drilled for a cotter so it can't be locked. You could take off your main spring and have a close tolerance adapter machined to it and your tailwheel to reduce/eliminate the twisting action.

You could cut off the loop and then you won't notice when your bolt rotates which it probably was doing before.

I don't know how you might choose to obtain approval for those suggestions or how well they may work, but it may help to CHANGE the NUT to a self-locking type, all metal(AN363) will likely be most effective.
https://www.aircraftspruce.com/catalog/ ... ckkey=3949

What is the nut size? I may order a couple and am not where I can measure the threaded portion of the bolt right now. Figured someone would have the size committed to memory.

This nut coming loose has been a issue with me and the upper bolt attaching the spring to the airframe coming loose also has given me grief. Tried torquing both nuts to their respective torques and no luck. So in desperation replaced both bolts with MS grade bolts and used AN363 nuts . No issues since. [use the correct type of washers also].

PS. A “friend “ told me it was due to my landing practices. I wheel it on on and hold the tail up as long as possible and let the tail come down . Some times it bounces down . Personally I think there is a lot of stress on the tail wheel in a 3 point landing .

170C wrote:What is the nut size? I may order a couple and am not where I can measure the threaded portion of the bolt right now. Figured someone would have the size committed to memory.

AN363-720 as per the IPC.