1.   Ensure you do not have any washers on the long thru bolt of the
donut stack
2.   Consider whether you should periodically remove the horizontal thru
bolt (connecting the lower donut stack casting to the gear leg) to
visually check the stop nut for security.  I do nut believe that you can
see this nut without disassembly.

Tom, et al,

 

Re: 1, The washers are useful, get a longer bolt.

 

Re: 2, I cannot conceive of a "lock-nut" coming undone unless there is a rotating force.  Washers can be helpful in avoiding the consequences of this force.  In any event, if there is evidence of any rotation (maybe even if there is not), consider a drilled bolt and castle nut with a cotter key to completely keep the nut from coming off.  Or, better yet, consider the TK5 air-oleo struts that are so much cheaper than a ground down wing, etc.