Track loader repairs

Working on a 1960's Caterpillar 955h crawler loader:
0:00 bring in garage
1:29 New top roller
4:57 Remove exhaust elbow
14:13 new seat
22:05 Install new exhaust elbow
23:45 Demonstrate bad starter
25:20 Install muffler
27:18 remove starter to get rebuilt
31:46 Demonstrate roller not turning
33:11 Engine oil change
35:35 digging in shale
45:41 Make exhaust gasket
49:10 more digging, also using a Ex100 excavator, Cat 950 wheel loader, and Takeuchi TL12 compact track loader
Ebay roller listing: (the winning bidder refused to pay) https://www.ebay.com/itm/184739763847