Diff preload and gasket thickness (compressed)
Hi,
How do I measure (compressed) gasket thickness within 1 thousands of an inch (0,025mm)? The Haynes manual seems to rely heavily on a certain type of OEM gasket with a set thickness, but that doesn’t seem to fly anymore. The YouTube’s and forums I saw measured the gap without gasket and then added “the thickness” of the gasket. But since that gasket is so much thicker than the gap needed that sounds like a lot of room for error. I’ve searched the forum (and the internet) for information on this but couldn’t find it. But maybe I’m just bad at searching, others must have had this question before!
I had a potjoint with too much play so I removed the diff cover and ordered a new cover and 2 different new gaskets. Because it was the cover side without the shims I was hoping 1 of those gaskets would be the same thickness as the one that was on there so I don’t have the pull the diff covers on both sides of the diff. The engine is still in the car.
The preload should be between 1 and 2 thou (0,025 or 0,05mm). But that means I should know the thickness of the gasket in compressed state in extreme accuracy. I have a micrometer so I can measure the thickness of the old and new gaskets, but not compressed. 0,025mm is so small, even different measurements of the same gasket at different places shows a tiny difference. And a tiny difference in pressure you put on the multimeter also influences the outcome a bit.
The old gasket seems to be 0,35 to 0,40mm thick, depending on pressure applied. 1 of the new gaskets (22A1611) is about the same thickness but that could still be +/- 0,01 or 0,02mm! (there is no info on those gaskets as far as I can find). The diff is low milage. I think the bushing went bad after the exhaust took a hit and the LCB reached the potjoint. So I was thinking of just putting that one in place and forget about it, but it seems incredible inaccurate if the preload is so tiny.
Very long story short (sorry, I’m typing on my phone and English is not my native language): how do I accurately measure the compressed gasket thickness within 1 thou / 0,025mm or less..?
Best regards and thanks, Pieter
Posted: May 06, 2023 10:39 AM