More diff woes 
1972 Sprint. Lotus replacement chassis in mid 1990s.
Prior to fitting new driveshafts I removed the diff. to attend to a slight leak. Refitting has shown up a very tight clearance issue at the bottom. I’ve replaced the original fit 3mm spreader washers with new 1.7mm ones but my cardboard feeler gauge is still a very snug fit at 0.57mm.
The diff mounts were of course replaced at the same time as the chassis but have virtually no road use, maybe 1200 miles.
Could they have deteriorated to such an extent just by sitting? They appear to be fine.
I have read comments regarding the build quality/accuracy of replacement chassis ( mine needed to be relieved to ensure the exhaust manifold didn’t knock) and I’ve measured the distance between top and bottom chassis rails at the diff mounts as 250mm left side and 260mm right side (approx).
The bottom rail isn’t deformed by jacking.
Can anyone with a Lotus chassis confirm those figures as it isn’t detailed in the manual drawing.