Service Manual: -
Dis-assembly/Re-assembly
Screws: Canon

Full CLA: 16-18 hrs.
front of lens rotates and is a T3.5 (T3.7 for newer models)
Clean optics: 5-6 hrs.
tracking (not built in): see notes
try loosening mount and sub-mount to improve centering (trial and error process). Canon says tracking adjustment is located in zoom group which required full disassembly.
Centering: 1-2 hrs.
under front ring are set screws in front group, try adjusting to improve centering.
Iris only: 2 hrs.
Focus only: 8-10 hrs.
lens can split. screws located under focus scale. remove 9 socket heads and black set screws located towards front of lens (not socket heads located towards rear of lens in same location. splitting lens will mess up field (set screws)
Mount conversion: see notes
must go to Canon for conversion.