1098 Gearbox 3rd Motion shaft bearing

[northernboy]

Just overhauling my gearbox and have bought a new set of bearings from ESM and apparently the original bearings had a slightly wider inner race case than the outer race case. New bearings however have the same width inner and outer race so ESM supply an additional washer to act as a spacer. However I note this washer is not flat. The ESM product photo sort of shows this but is much more obvious when examined up close. Why would this be - is it a sort of crush washer ? - any ideas or throughs ?

[svenedin]

See this guide (perhaps you are using it already). It's a shim

https://www.dorsetmmoc.co.uk/wordpress/ ... ebuild.pdf

[northernboy]

Yes - excellent guide indeed - the washer in the guide looks flat but difficult to tell

My question is why a shim would not be flat

I have also been following this excellent video series on YouTube

https://youtu.be/H6_r0RQiaO4?feature=shared

[svenedin]

Good question to which I don't know the answer. If you fit the shim on the shaft one way and then the other does it become apparent? Presumably the bearing will not run properly with the shim back to front? Otherwise maybe give ESM a ring tomorrow!

Stephen

[northernboy]

Thanks Stephen - no obvious difference which way it goes - I will phone them tomorrow - thanks

[HARBER07]

That is not what I would called a shim. A shim would be a precision ground washer or made from very precise material like shim steel.

That looks like it is simply a cheap punched steel washer. I suspect the conical shape is to get it to act a little bit like a Belleville washer, taking up the tolerances in the manufacturing process.

Having never taken a gearbox like these apart I couldn’t tell you which way round it should go, but I suspect that is what is happening in this case.

[svenedin]

Spacer/shim/washer. Whatever we call it, the thing is needed because the bearing is not the same as the original. Yes shims are often precision ground but the dictionary definition of the word shim does not imply this but rather what the function is. For instance, shims might be wooden wedges in a door frame.

Stephen

[HARBER07]

But we’re not talking about wooden door frames are we Stephen, in your example they would be called packers. We are talking about cars, therefore some consistency on terminology is required.

We have already determined why the washer exists, I was merely trying to add input to the conversation about why the washer is a certain shape. It’s what forums are for. It’s a discussion.

If I have somehow offended you then I apologise. If my experiences and expertise are not required on this forum then I wish you all the best and I will no longer contribute

[northernboy]

I spoke to ESM and the person on the phone was aware of this particular item but could not explain why it would not be flat but will raise the question with their gearbox person. Lets see what they have to say next week.

Logic determines if new replacement bearings are thinner that the original then a spacer, shim or whatever is required to make up that difference.

I would have though this would be a precision component made to close tolerances. The supplied item looks like a pressed washer that is neither flat or precision made and was starting to rust!

I am minded to measure the new and old bearing and buy precision hardened steel shim/washer to make up the difference.

I will update when I hear back from ESM

[jaekl]

In the factory build there are shims between the inner race and the mating cover for both the first and third motion shafts. What is the function? To either clamp the inner race or prevent it from moving? How well it does that depends on the extra height of the stack versus the depth of the total cavity. But it can't be too high or the gasket is defeated. And what about thermal expansion. To me a Belleville washer would be a better idea for both application and assembly line. As supplied are you to also include the flat shims? How are you to determine the appropriate thickness>

[les]

Seems a minor point for someone to say goodbye to the forum but of course they have a perfect right to do so. One needs a little tolerance sometimes on a forum.

[svenedin]

But we’re not talking about wooden door frames are we Stephen, in your example they would be called packers. We are talking about cars, therefore some consistency on terminology is required.

We have already determined why the washer exists, I was merely trying to add input to the conversation about why the washer is a certain shape. It’s what forums are for. It’s a discussion.

If I have somehow offended you then I apologise. If my experiences and expertise are not required on this forum then I wish you all the best and I will no longer contribute

I am sorry if I caused offence. Personally, I am not in the slightest bit upset. Yes absolutely your contribution is appreciated.

Stephen

[northernboy]

I have had an update from ESM and the guy who builds their gearboxes says he has used this type of Belleville washer without issue but ESM could not explain why a Belleville type washer would be used in this situation. Interestingly, I have been told they no longer issue the Belleville type and now supply a flat packing washer with this bearing set which makes more sense to me ------ Umm

ESM have agreed to send me one free of charge.

Hope we can now close this issue

Thanks for everyone's contribution - we all help one another