Some discussion on Piper SB 1379 popped up another board this week. It essentially requires replacement of the rudder post if it's made from 1025 steel. Ones with 4130N, are exempt. It covers everything from the J3C to the PA-22, and both civilian and military builds. If you built something that uses the same rudder, or similar construction I'd advise doing the SB.

Reading between the lines, there have been a couple of failures of the rudder post at approximately 1/2 it's height. Reference is made to corrosion thinning the tube wall there, but some have noted that at least 3 of the failures had beacons mounted at the top of the rudders.