I think the year was 1979 and I was flying my huge bi-plane 72"+, a Bi-Stormer in Wormwood Scrubs open space London UK, where I usually flew my model planes after the soccer field was cleared of players and goal posts. I lived in Harlesden...
It’s probably not the arm but the “shim” that allows the arm to rotate when folding it. most arms do see some damage in a crash but really the only way to tell for sure is to take off the arm and examine each component with your eyes..
For arms...
That was it. Once I sorted through a couple videos I found one specifically explaining that. Got the parts, installed and heading out to fly now! Thanks!