Primary pinion bearing lubrication

MFC · Sep 14, 2017

Hi All,

Currently rebuild a Series 1 box and a question has come to mind - how is the pinion bearing (the big one in the case lubricated). When you look at the back of the bearing from the gearbox side there is a oil shield which I am guessing is to stop oil!! but how does oil lubricate it??
Pic attached
I am sure the book says the shield should be on the inside but can't see the logic??
Thanks for you comments in advance!

Extreedoc · Sep 14, 2017

The bearing should be open into the gearbox, I can't understand why they've sold you a shielded one. You can always dig out the shield with a pointy thing or better still get the right, unshielded bearing. The oil is kept in by the cover inside the bell housing and the oil seal fitted in that cover.

jamesmartin · Sep 14, 2017

that is correct for a pre all synchro box, the shield is slightly dished away from bearing or should be so oil reaches bearing but oil isnt sprayed in large amounts which would mean oil passing through release bearing tube as theres no seal just a screw thread

MFC · Sep 14, 2017

Thanks for that, the bearing is not shielded and the shield you can see is fitted on the primary pinion before the bearing (at lease that was how it came off) hence giving the appearance of a shielded bearing. The shield is in the 2a/3 haynes manual (petrol p84) and in my Series 1 WSM and Parts manual but very unclear which side it should be on - although the haynes manual shows gear side. Is it possible that the bearing is lubed from the bell housing side ie oil migrates through layshaft bearing etc???

MFC · Sep 14, 2017

jamesmartin said:
that is correct for a pre all synchro box, the shield is slightly dished away from bearing or should be so oil reaches bearing but oil isnt sprayed in large amounts which would mean oil passing through release bearing tube as theres no seal just a screw thread

Thanks James, then my issue could be that the oil shield is flat - maybe of a later model, IT just currently looks wrong!!

MFC · Sep 14, 2017

jamesmartin said:
that is correct for a pre all synchro box, the shield is slightly dished away from bearing or should be so oil reaches bearing but oil isnt sprayed in large amounts which would mean oil passing through release bearing tube as theres no seal just a screw thread

Sorry James when you say that is correct do you mean the pic is correct or the previous answer from Extreedoc is correct???

jamesmartin · Sep 14, 2017

MFC said:
Thanks James, then my issue could be that the oil shield is flat - maybe of a later model, IT just currently looks wrong!!

turn the shield round

Extreedoc · Sep 14, 2017

Misunderstanding here, I thought you were talking about having been sold a shielded bearing.

jamesmartin · Sep 14, 2017

MFC said:
Sorry James when you say that is correct do you mean the pic is correct or the previous answer from Extreedoc is correct???

you need to have the shield there

MFC · Sep 14, 2017

jamesmartin said:
you need to have the shield there

Thanks James, will have a look and see if flipping it will allow some oil in - if not may have to bend it slightly

jamesmartin · Sep 14, 2017

MFC said:
Thanks James, will have a look and see if flipping it will allow some oil in - if not may have to bend it slightly

it doesnt need much at all but usually you find one side fits tighter against the bearing than the other,you want it to be the other

Primary pinion bearing lubrication

MFC

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Extreedoc

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jamesmartin

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MFC

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MFC

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MFC

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jamesmartin

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Extreedoc

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jamesmartin

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MFC

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jamesmartin

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