Armed with my technical docs, I have attacked the truck with Knowledge and the power of carefully directed violence!
Contrivance Extracted, and cleaned and freed off, and reinstalled...
...and it binds up when reinstalled. So more cleaning, and scraping, and scrubbing, and cleaning, and...
it still binds up when reinstalled fully. Possibly the housing is distorted? It was incredibly difficult to remove the mechanism. And it only binds up when it's fully seated...
Anyway, then my other boss got back in, saw me refitting this mechanism again, pulled a face like I'd grown another head and said "Just replace the fucking turbo"
So we'll see whether or not the customer thinks the truck is worth putting a turbo into, at this point! (Probably not.)
Customer decided it wasn't worth putting a turbo into, said they'd rather just scrap the truck.
But, folks... folks: I only went and got it working again! Sure, I had to leave out a gasket to give me the clearance in the housing for the vanes to actuate, but it's all back together and running.
And I took it out on a test-drive, and the warning light stayed off. So then I decided I'd take it up the torture-test hill (113 meters of rise over 2.4km. 85 meters of which is in the latter half. If something has a problem, that hill will find it.), and it went up there faster than previously in a higher gear, without throwing a horrible warning about overboost!
So that's a resounding success, I'd say! The missing gasket probably shortens the life of the turbo, but seeing as they were already expecting to write the truck off, anything else they get from now is a bonus.