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MG Midget and Sprite Technical - Front wheel bearings

Hi,

have an advisory on my last MOT that the o/side front wheel bearing requires attention. There is some slight movement so if re-shimming doesn't work it'll need replacement.
Moss want about £50 for the two bearings however this place only wants £13.50 for them
http://cgi.ebay.co.uk/AUSTIN-A35-A40-RILEY-1-5-FRONT-WHEEL-BEARING-KIT-NEW-/260703113121?_trksid=p4340.m263&_trkparms=algo%3DSIC%26its%3DI%252BC%26itu%3DUCI%252BIA%252BUA%252BIEW%252BFICS%252BUFI%26otn%3D15%26pmod%3D250686555308%26ps%3D63%26clkid%3D1380995507024051780
Has anyone used them and if so what's the quality like?

Thanks

Jeremy


Jeremy 3

Jeremy,

Actually Moss list GHK1142 (wheel bearing kit) for front @ £19.96 - two bearing and oil seal.

There has been long debate about the problems of incorrectly machined bearings - new being worse than existing bearings when fitted etc - check the archives.
Face adjusted bearing are available from specialists and are expensive - however ongoing confusion regarding rear radius onto stub axle.

Check what Moss have to say regarding the individual bearing costs - are they the specially 'face adjusted' ones - seems a little strange else.

No shimming is possible with Spridget bearings.

R.
richard boobier

Ofcourse shimming is possible, but then you'll have to measure the bearings, compute the free play (if there) and shim the spacer as needed or shorten the spacer as needed. Not an easy job without some experience in exact measuring.
Alex G Matla

Shortening a cast spacer is not shimming !

Adding shims only increase tolerances.

These techniques are only disscussed in relation to spridget front w/b's as the quality/correctness of parts is now so poorly controlled.

R.
richard boobier

I meant shimming as a matter of speech. If you shorten the spacer (like I did) maybe the next set of bearings may need a shim. (like I didn't)
Alex G Matla

A few years ago I researched this problem along with a friend of mine who was a director at NSK (NSK took over the original bearing manufacturer to BMC the company were called RHP)

Anyway with reference to the original specication drawings one could see that the Spridget front wheel bearings (and those fitted to Morris Minors and other BMC models) were specials that had face adjustment.

Subsequently these original spec bearings were only supplied to BMC and were subsequently discontinued when BMC/Leyland no longer required them.

So the problem is that nowadays the replacements for these bearings whilst having similar dimensions differ in a couple of ways. Primarily they are NOT face adjusted and so typically when fitted to the Spriget hub will most always have a small amount of play even when brand new. This can be overcome as described by Alex above by machining the internal spacer, however this is a tricky business and if it is machined too short the new bearings will fail within a short period of time and may even sieze with disasterous effects.

Fortunately there are replacement bearings available with similar dimensions that are face adjusted and when fitted in the normal manner will fit correctly and take out the play that other bearings display. The problem is that these are expensive, costing in the region of £100 a pair (one hub) So that is £200 for both front wheels)

This I believed at the time was a perfect yet costly resolution to the issue and my front wheels have these installed with no play and are performing perfectly.

Then a little while ago another enthusiast (Tom) looked into the problem and identified a further issue that I had not noted on the original diagram. Another dimension that was special to the original bearings was the inner radius of the inner race. The result of this dimension is that ANY bearing other than the original could when fitted not seat fully with the stub axle. As this is the case with ALL bearings then one must assume that the vast majority of Spridget and Moggies are running around in this condition without issue. In fact the only issue in the UK is that we all struggle at MOT time with play in the front wheel bearing which can be cured by the purchase and fitting of face adjusted bearings, the only other alternative is to try and purchase some NOS RHP original bearings from a supplier. I have seen occassions where these are available although most dealers know their value and charge over £100 a hub!

Bearing numbers as follows

Original bearings
34 LJT 25
3 MJT 17


Replacement Face Adjusted
NSK 7303BEAT85SUN and 7205BEAT85SUN or in SKF no's 7303BECBP 7205BECBP

Modern equivelent bearings that will guarentee loose bearings
7303 and 7205

I hope this is a clear description of essentially a dificult issue.

Best of Luck!

Robert (Bob) Midget Turbo

OR circumvent the issue by using taper bearings instead, as used on many race cars.
David Smith

Taper bearings will not be as good as the replacement face adjusted bearings and will also suffer from not fitting to the stub axle shoulder the same as the face adjustment.

I would always choose the replacement face adjusted over taper bearing everytime.
Robert (Bob) Midget Turbo

Having worked for the original manufacturer of these bearings I would advise taking Bobs advice and although expensive get the originals if you can or the NSK alternative. You will then get many years of trouble free motoring and MoTs from them. Anything else is liable to give you trouble unless you are extremely lucky.

Trev
T Mason

Bob, thanks for your very informative post.
I will make a copy of it for reference.

I have always wondered why it is almost impossible to eliminate play, even with new bearings, on a midget.

It all makes sense now.
JB Anderson

I am with Bob, and Trev, the OEM bearings are fit and forget. They are expensive because they are now being made in small batches, by one company (Ransome and Marles) for a rather small population of cars that use them (A30 ~ Midget).

The alternatives are either not good (not face adjusted, incorrectly small inner radius), or if careful consideration of all of the key factors was confirmed, could maybe be OK (like, tapered bearings, if properly shimmed the same way as an MGB's are shimmed, Speedwell sells a kit that claims to meet this), but in all cases, ONLY if the inner bearing has the proper inner radius, and only if any such shimming is done properly (I don't recommend trying to shim ball bearings, because of the nature of how they are pressed into the hub and how difficult it is to remove them to adjust the shimming without blowing them apart).

By the way, John Twist states in his youtube training video on front wheel bearings that they should last the life of the car, if properly installed. This knowledge makes it easier to swallow the high purchase price of the OEM bearings, compared to possibly having to pay for replacing ones that don't fit properly, again in the future.

For reference, here is an article combining the excellent input from Bob, and Tom (Smith), and some more from John Twist and the kind folks over at Ransome and Marles (the division of NSK that Bob refers to, which is what is left of RHP, which is where Trev worked). I hope that it is helpful:

http://www.mgexperience.net/article/mg-midget-wheel-bearings.html

(and, as always, I welcome your input to help improve it further).
Norm
Norm Kerr

Jeremy

Take Bobs advice. I had issues with my front wheel bearings. I bought some from Moss (IIRC) but they where worse than the ones I took off!!!

I then posted here and was advised by Bob to seek out the original spec. I managed to get some from here:


Bearings Impex
Queen Street
Crewe
Cheshire CW1 4AQ
01270 585211

They were £24.50 and £28.60 each + vat, that was early last year.

As Blackadder would say they are now as tight as a tight thing.





Tony Brough

Crikey,

here's me thinking bearings were relatively a simple issue!
Excuse my ignorance, all this is way over my head but what is meant by faced bearings?
Thanks for the tip Tony - Crewe isn't too far from home so I'll give them a ring.

Jeremy
Jeremy 3

jeremy3 - if you read the article that Norm kindly hotlinked for you, you will find out! Here is an opportunity to learn - seize it, it's not hard, and I'd be surprised if it was really 'way over your head'
David Smith

just found a supplyer that advertises the proper SKF bearings mentioned by Bob for €75,- per side incl vat

And might have found a German supplier who is cheaper
Onno Könemann

Onno, it would be interesting to see a set of those SKF bearings to find out if they have a large enough inner radius (>2mm).

Norm
Norm Kerr

Norm,

A quick look on the SKF site seems to indicate the radius concerned for the 7205BECBP is 1mm maximum so the bearing would have to be shimmed so it seated correctly against the inner end face of the stub axle.

http://www.skf.com/skf/productcatalogue/Forwarder?action=PPP〈=en&imperial=false&windowName=null&perfid=123002&prodid=1230020205

The link needs to be copied and pasted by the seem of it.
David Billington

Correct David

The industry standard at present for that size of bearing would always be 1mm unless it was a "special". Simple reason for this is to give the inner face as much land as possible to seat.

The problem is with the stub axle design. Some are OK for 1mm and some are not and make full use of the 2mm tollerance.

I will repeat what I stated above, all modern bearings whether cheap and nasty, or face adjusted or taper roller would be 1mm so all would have the same problem with the stub axle. Fortunately IMO it is not such a big problem and from our point of view a wheel bearing without play is a good if not perfect result.

Norm the company you refer to is not R and M and they are not a division of NSK? I believe they are using the name and selling NOS bearings. To my knowledge nobody at present is making the original spec bearings although I do know of a company who would make them if there was a need. The company in question generally modify an existing bearing to suit under licence from someone like NSK. On this occassion they would machine a face adjusted inner race to suit, not a terribly difficult job although the initial cost of the bearings is somewhat high.
Bob Turbo Midget England

The company Norm refers to is actually a supplier, not a manufacturer, called Orinoco Bearings Ltd of Leeds. They specialise in all the old and rare bearings from the old RHP and many other firms. If they haven't got it they can get it made but I do not know who by.

Personally I am not a lover of SKF. Back in the 70s Rolls Royce Aero Engines left RHP and went to SKF because they were cheaper. Within 6 months they were back as they were unhappy with the quality of SKF.

Trev
T Mason

Trev is correct. When I discussed with the folks at Orinoco, they said that they do exactly that, and make new ones in batches of 10 whenever they are out of the NOS, hence the high price (low volume manufacture).


Norm
Norm Kerr

Hi Trev

Yes I think they must get them made by the company I am aware of. My friend at NSK introduced me to the company telling me they would make/modify existing bearings to suit original specs. I guess the company advertising as R and M probably get them made there.
Robert (Bob) Midget Turbo

This thread was discussed between 16/07/2011 and 18/07/2011

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