Is your Leica M6 giving you problems. Here's the Leica M6 repair manual.
I acquired a whole set of Leica repair manuals on microfiche about 25 years ago when a camera repair shop went out of business. I also have the manuals for a M4-2, M4-P, MD-2, Leica M lenses, R3 MOT, R4, R lenses, Trinovid Binoculars, and the US Army technical repair manual for the M3.
Speaking of the Army version of the M3, I was actually issued a body and the 35mm and 50mm lenses to use as a backup for my Nikon system. The body was called a Leica KE-7A. I used it for a couple of years until we turned all of our film cameras in to go digital. That was in 1995.