19 replies to this topic

[johnR]

Yes, to be fair it is mentioned on the Minispares product description for the bearing but I didn't notice it when I ordered so went with the Haynes/thread pre-load figure. A note on the bearing packaging would be more obvious but luckily I can easily re-shim mine now.

[Sprocket]

Why would it be on the packaging? It's a catalogue bearing. What I mean by that is it is a generic bearing from the RHP catalogue, it could be used in any number of different machines other than a Mini gearbox

 

To be fair, the late royal blue Haynes book is rubbish. The older sky blue one is much better, and it has both pre-load settings listed and describes the difference in bearings, You cant really blame Rover, Minispares or the Haynes manual, or anyone else really. Rover no longer exists and the reason why the thrust type bearing no longer exists. The next best thing is a catalogue bearing that Minispares  and others stock (and incidentally Minispares have highlighted the difference, has anyone else?). The people behind Haynes are not in the parts Business and only go off the last factory data to generate their books (auto data is the same) so differences do creep in when obsolete parts are superseded beyond their control. Basically   happens.

[johnR]

Don't get me wrong Sprocket, I'm not blaming anyone else - it was my inexperience that caused me to miss the spec - that's why the forum is so useful to us newcomers, without it I wouldn't have realised. In fact on re-checking my diff preload it is within tolerance for the bearings but it's good to be sure.

[country clubman]

I'm a bit late to this party but thought would join in anyway.

 

I was struggling to get my head around the shimming maths for the diffs, sorry none of the above explanations of it helped, probably made me more perplexed! the haynes helped a little, but only when I started drawing diagrams (call me stupid) did it fall into place.

 

So I came up with another way of working it out(hopefully nice and simple), which amounts to the same sums as other people, but if this way helped me it might help others and help others get their head around it.

 

If you have a compressed gasket of .012 and when cover is on the gap is .004(where the gasket sits).

Simply subtract .012 - .004=.008 and all you need to do then is think this is the gap between the bearing and the cover that pushes up against the bearing.

So if you have a gap of .008 and if you add .008 of shims no gap no preload, so .009 give you .001 preload, .010 gives .002 preload so on until required preload acheived.

Just to demonstrate again with different gap same gasket size, gap .002 - gasket.012= .010 gap next to bearing, add the preload amount onto gap next to bearing, shim it up .014 for preload of .004.

 

Just to throw something else into the mix as well, anyone ideas on these taper diff bearings for coopers? what would preload be on these?

http://www.shop4auto...taper-diff-pin/

[country clubman]

If you have a compressed gasket of .012 and when cover is on the gap is .004(where the gasket sits).

Simply subtract .012 - .004=.008 and all you need to do then is think this is the gap between the bearing and the cover that pushes up against the bearing.

So if you have a gap of .008 and if you add .008 of shims no gap no preload, so .009 give you .001 preload, .010 gives .002 preload so on until required preload acheived.

Just to demonstrate again with different gap same gasket size, gap .002 - gasket.012= .010 gap next to bearing, add the preload amount onto gap next to bearing, shim it up .014 for preload of .004.

Ok quoting myself now(I have lost it), just realised what I have wrote is exactly the same as ethal's maths, what through me was the opening statment "need shim of equal thickness of compressed gasket", which wouldn't always be the case only in that example, plus I was still scratching my head! But once you get your head around it, it all makes sense even what over people have written.

Edited by country clubman, 08 May 2018 - 09:25 PM.