So where was the case leaking? The HEV had no signs of rust, the case back and crystal seals were good. Rust visible at the case tube and at both pushers:
Parts! At least some of them that I had on hand and didn't have to order. The missing part is in this photo...
Base movement is assembled:
Amplitude looks good in the 290's, at least in this position:
Carry on with 6 positions at full wind:
Results - this is an 1154, which is a chronometer grade movement, so the requirements for performance at full wind are that when measured over 5 positions, the Delta should not exceed 12 seconds, and that the average rate over those positions should fall between 0 and +6 seconds per day. Here I have tested with one additional position, and I have 6.4 seconds Delta, so a little more than 1/2 of what is allowed, and the average rate is 3.4 seconds per day (I will probably adjust this closer to zero before this is all done):
So for a movement that was supposedly not worth saving, it's performing pretty well I think. This is why any lever movement based on the 7750 is something I always look forward to working on - they just work and work well. They have to be very badly abused before they give you troubles.