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MG Midget and Sprite Technical - Bearing to tight?



I replaced the left front bearings for an face adjusted set with the right radius. It needed 0,030 mm of rings, because it was sloppy. It was just right after 0,030. After a few thousand miles it was sloppy again, but I could not find any wear in the bearings. The Hubs where the bearings touch where scored. I flattened it more or less and tried a few combinations: 0,050 was to tight, 0,035 sloppy. So 0,040 would be right but I did not have this combination. With 0,045 the wheel could just turn one turn by itself . So to tight. After 100 miles and fast cornering, it did not adjust.
Question: Will I make more miles with 0.045 or go to the shop and buy 0,040?
Flip



Flip Brühl

Flip, questions.

You say scored hubs, but your picture is a spindle. What is worn/scored? Spindle or hub?

Are you certain you are using the *original* spacer in each hub? It matters because they vary a little in length, and appear to have been matched at the factory.

Whose face adjusted bearing did you use?
anamnesis

Both, but I do not have a photo of the hub. The spindle must have been in a vice. It took me haf a day but they are both smoothened and flat enough now.
I do not know who supplied the bearings on E bay, They have bronze inserts and looked old (the grease was hard) but unused.

Flip
Flip Brühl

Flip,
any part numbers on the bearings?

Inner brass cage bearings were 34 LJT 25.



Nigel Atkins

Ok then. Since they are original rhp/r&m bearings, it seems to me there are 3 possibilities.

1. They were used and sold as new. Hopefully not.

2. The spacer is slightly too long.

3. The wear in the hub, the outer section, is allowing the outer race to move. Shims won't fix that.

How easily does the outer bearing 'press' into the hub?

I wonder if you could speedi sleeve the outer bearing. This was discussed not longer regarding a rear hub.
anamnesis

Sorry Flip. I've got a bad head cold.

If you are adding shims because it's **too tight**, as per title, then the SPACER is too short, not long as I wrote earlier.

But I'm confused.

I assumed you meant shims, but you write RINGS. And you are adding rings, because it is sloppy, not too tight as per title.

Are you puting these rings under the outer race of the outer bearing?



anamnesis

Sorry for my English; yes shims under the outer race of the outer bearing
Flip Brühl

Ok, understood.

So is the outer race a good tight press fit in the hub?

If not, then that may be a problem.

Having a 'thick' shim under that outer race, reduces the amount of internal clearance in the bearing as you found. And that may well have been enough to 'clamp' the outer race and stop it moving in the hub.

But then because you had too little clearance, you may have put a little wear in the bearing by driving it like that for 3000 miles.

Yes, you are on the right path by increasing the shim thickness, but first make sure the outer race isn't able to move in the hub.

Also, did you remove all the old dry grease and replace with fresh grease?
anamnesis

Even though some may disagree I believe that taper roller bearings must be tightened up against the spacer and not the outer race housing. Slight freeplay is achieved by the appropriate thickness of shims between the spacer and inner race, not by backing off the retaining nut!

Jan T
J Targosz

Yes I could remove the outer race of the big bearing with my fingers from the hub, so it was to loose. I replaced it with loctite 6300. The outer smaller bearing was a correct tight fit.

Jan, it had to much free play ( I think because I had to remove some material from the hub).

It is not easy to get the right shims here in Holland. 5 years ago I could go to a shop nearby, Today they have an other international owner, name, location software and no counter... Shims ar not in their digital catalogue. . After Brexit delivery from the UK is not wat it was. And I am getting older.
What I can do is shorten the spacer.
Flip Brühl

Flip,
to get the original RHP bearings to fit on my midget I had to have a mate shorten a new spacer for it to match the hub space for whatever reason. In the Archive there's a whole thread with it in and photos, examples below.






Nigel Atkins

Flip
I'm a bit confused (normal)
Are you giving us the correct measurements
Just to convert over--The difference between your 0.030mm and 0.050mm is--0.020mm
converted 0.020mm is less than 1 thou. (.00078")
Hardly enough to go from too tight to too loose---

willy
William Revit

Yes Willy: one 0 to much: 0,5mm too tight and 0,35mm sloppy. Is it my age or do I drink too much?
Flip Brühl

The shims don't need to hardened and can be made from steel Coca Cola cans. The bodies can be cut with scissors but make certain there are no burs. I don't remember how thick the cans are but it is only a few thou. It is Essential the spindle nut is done up tight and free play provided by the length of the spacer and shims. If play is provided by backing off the nut the bearing will not last. It is preferable for the spacer to be a little short so shims can be added or removed as appropriate.

Jan T
J Targosz

Cheers Flip--i had a feeling that was the case but just thought I'd ask-----I don't believe it's your age or your drink for a minute , it's easy to get a bit mixed up converting between metric and imperial----At least you had a zero in front of the decimal point which is std practice for metric figures as against not so for imperial---
willy
William Revit

This thread was discussed between 19/08/2022 and 23/08/2022

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.