Thank you Klaus! Interesting to see the drawings after so many years
Much appreciated!
Well it's never too late, so future DIY can be prepared before they open the lens up!
Weak spot No1 Is the part page 4, #76
with the three little brackets for the three screws #77
They often loosen and they basically hold the front and rear together, the design is way to tiny and flimsy for such a big heavy lens.
Page 3, screws #59 as well as #49 can work loose
#14 with the three screws #13 are infinity focus setting
#71 is the unit that can be exchanged for the different types of mounts, Canon, Nikon etc.