I am surprised that a commercial CLA did not solve the issue (if I understand you right).
As you are a mechanic by profession you should dare a repair by yourself. On the net you'll find the original A-1 repair manual as well as several manuals by DIY people just for solving the squeal issue with type-A cameras.
I read the test report by Norman Goldberg when the A-1 first came out. He said due to its design the A-1 would be prone to lubricant dried out.