A very ugly Leitz Elmarit R 180mm f2 8 needing repair, part 01

Servicing an Elmarit - R 180mm f/2.8 lens. I was asked to look at the lens by my brother. I think he'd picked it up at a garage sale...I hope he only paid $5!
I was unable to find any service information, but eventually managed to find my way into the lens .
The best YouTube channel for lens repair that I know of is this one ‪@mikeno62‬
Kenneth has many, many useful videos.

Consumables used servicing camera bodies:
I use naphtha (cigarette lighter fluid) for cleaning metal parts. CRC Heavy Duty Lectra Clean for dried grease that the naphtha won’t dissolve. A generic wax and grease remover to soak mechanical parts prior to cleaning in an ultrasonic cleaner. Glass cleaned with normal domestic glass cleaner.
Parts are lubricated with Inox MX6 (a synthetic grease), Rocol Dry Molybdenum paste, MicroLubrol Helimax XP helicoid grease, graphite powder, or graphite grease as needed.
Leatherettes are glued back with Ados F2 adhesive.

Consumables used servicing shutter and lens assemblies:
Naphtha (cigarette lighter fluid), or occasionally CRC Heavy Duty Lectraclean. Lenses cleaned with normal domestic glass cleaner.
Parts are lubricated Rocol Dry Molybdenum paste, MicroLubrol Helimax XP helicoid grease, graphite powder, or graphite grease as needed.