Diff question

[PAULJ]

Hi, can anyone tell me if the bearings are the same for all ratio diffs that fit the moggy. Also is the preload setting the same. Im rebuilding a woolsley 1500 diff but only have moggy manual. I ask about the bearings because the 3.7 diff bearings are noisey bit I have a sound 4.2. seems daft to buy new bearings if I have a set in another diff.
Thanks

[bmcecosse]

Should all be interchangeable. Just put the 3.7 parts in the good final drive.

[Roni]

I am having a 3.7 crown wheel and pinion fitted to a Minor diff head. It is still underway but should be done soon.
Bearings are not necessarily the same size, especially the pinion shaft. You may find the 3.7 pinion shaft is thicker. There is also a bearing size difference in the housings of early, with filler bung, and late, without filler bung, housings. The diff carrier bearings appear to be the same. I can't help you with sizes as the parts are all away at the moment. All I can suggest is to dismantle and measure.
Another thing to consider is the Crown wheel offset.
I hope that I can give you some final results soon.

[bmcecosse]

Ooohh - yes - MOSS do list a bearing change along the way.... http://www.moss-europe.co.uk/Shop/ViewP ... exID=17078

[PAULJ]

Thanks for the info. I did see bearing change for late or early. the early ones are no longer available from moss anyway. I took the two diffs apart today. The side bearings are the same. Sound the same as well when spun so Im going to change all just need a puller to get them off. The two pinion bearings are taper roller (Timken) so should be easy to get hold of. The back pinion bearing and spacer looks a pig to get off. The Moss diagram doesn't show the spacer the one between the bearing and the crush spacer ??? Off to ebay now to look for some pullers unless anyone can recommend one

[daveyl]

I did one of those a few years ago. Not sure how easily the bearing (numbered '52' on the Moss diagram) can be removed without damage.
The key for fitting the Pinion shaft is to have a few different size shims (no. 74) because it's a trial and error basis to fit. (Although, if you have 2x diffs to work from, you should have enough spare). Basically if the fitted pinion is too tight to turn, add a larger shim - if too loose, use a smaller one. Defo worth investing in a digi micrometer.
I used the Haynes work-shop manual. It is the one and only time I've ever fitted a new diff, so maybe I got lucky. But I did use new bearings though.

[Declan_Burns]

Paul,
I'm about to take on a crown wheel and pinion interchange from 5.125 to 4.3 using MGA CWP on my MG TD and have done quite a bit of research into it. The guys who do this on a regular basis recommended this type of puller to remove the rear pinion bearing. They use dry ice on refitting.
http://www.ebay.co.uk/itm/PRO-QUL-2-PC- ... 1c1b5b9a19
They also use VW beetle 1200cc crankshaft shims which are difficult to source but available in USA. Moss USA also have shims in various sizes.


Regards
Declan

[frame][/frame]
Photo:MGA Pinion with rear bearing

[bmcecosse]

Yes that is the puller you would need - but if the bearing looks ok on the pinion - shaft - leave it alone ! These bearings don't have a huge amount of work to do - so unless run seriously short of oil - should last a long long time.

[PAULJ]

Ha, tis just the kit Im getting. Something in the diff is whining and I can see nothing wrong with any of the bearings or the crown and pinion. All for bearings look ok. The side bearings are a bit Rattley when cleaned and dried but the races and balls look good. With a squirt of oil they are quiet. I don't intend to change one bearing at a time as from what I have read every time you undo the flange bolt you should change the crush spacer. They are £9 ago. I was told by a chap with years of experience that if you are changing bearings that you shouldn't need to re shim as shims are to allow for differences in castings. Bearings are made to a very high standard so should be the same. That's only if your keeping everything except bearings. Sort of makes scene. The side bearings, I found out today will pull apart. The outer race comes off allowing the balls to fall out of there cage. This leaves the inner race in place. You can check all the balls and tracks. I think Im just going to replace the crush spacer first and torque it properly this time. Do all the backlash measurements and check mesh with blue. Put the diff back in and see. If still noisy change the bearings. That's a Plan

[les]

Yes that is the puller you would need - but if the bearing looks ok on the pinion - shaft - leave it alone ! These bearings don't have a huge amount of work to do - so unless run seriously short of oil - should last a long long time.

Unlike the pitted rollers in that picture!

[bmcecosse]

I wouldn't say they are 'pitted' - just nicely run in I think. I would reuse them without the slightest qualm......

[les]

Put your specs on Roy, the ends are well picked up.

[Declan_Burns]

Put your specs on Roy, the ends are well picked up.

I couldn't agree more-those bearings are being replaced as they are totally pitted and useless. Well spotted! I have no intention of re-using bearings in that condition. The pinion and crown wheel in my case are fine. It is wise to replace all the bearings which I intend to do-both pinion bearings and also the angular contact bearings on the carrier. I only posted that photo to show how the bearing is fitted and why that particular type of puller is recommended.
Regards
Declan

[bmcecosse]

I see the marks on the end - but I suspect that part of the roiller has perhaps not been running on the track. The rest of the rollers looks fine..... But we are discussing a humble Minor axle - and I agree for an MG TC perhaps more stringent rules will apply!

[les]

Rollers ends don't normally run outside of the outer race, if they did the bearing would be unbelievably worn!
btw did you watch that Guy Martin programme the other day--re steam engine?

[bmcecosse]

Well - I don't know what has been happening with these rollers- I agree I would renew them if I had a TC (I wish!!) but I would use them in a MInor. And yes - the SVR program - it was very much simplified of course, and discussing it with others today we are all agreed that the program was 'ok' - but it would be SO much better without the awful Guy Martin who is a complete prat. Such a marvel - can turn his hand to anything at all!! He's trying to be Fred Dibnah - and failing miserably. He also thinks 'imperial' measurement is .2mm, he mixes up his connecting rod and his coupling rod, he constantly refers to a 'train' when he means Locomotive , and he thinks the vacuum gauges are showing 'pressure'.... Oh dear. And the sideburns are just SO annoying..........

[PAULJ]

Thanks Les for the info on the puller. I take it that spacer with the numbers on comes off with the bearing. That is not shown on the moss diagram as a part. I saw the Guy Martin thing the other night. Very good. The man is a God in my eyes. Im a TT fan and have met him. Mad as a fish in petrol. he got the gig because of the way he comes across in the film Closer to the edge. All about the TT. Hows that for going off subject.
Rollers not sitting in the race ???? I think that was a statement typed before it was thought about ops

[bmcecosse]

No - I can't see how else they have been pitted like that - perhaps 'just' touching the edge - something like that. Anyone got a better explanation??

[les]

It's the same effect that occurs with the gearbox layshaft and needle bearing, the surface 'picks up' and appears as pitting. Most layshafts have this on inspection.

[bmcecosse]

Indeed - but along the length of the needle rollers - not just one wee bit at the end....