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MG Midget and Sprite Technical - Front wheel bearings (groan - again)

But perhaps an interesting photo first... I had the inner race for the inboard bearing stuck on the stub axle. Got it off last night using a bearing puller, and found what you can see in the photo. The actual race part has some damage to it, but it appears to be a manufacturing fault?
To my knowledge the bearings have never been off the car, it's done 76k miles. They felt ok before removal, and a ball seems to roll over the damaged surface area ok. I can only concluded that it has always been like that - and definitely been like that for the last 20 years.

Anyways, the summary is that I think I'm going to fit new bearings. I've read a bit about problems with some replacement bearings, and that I need some 'face-adjusted' ones. I saw a post from Guy or some other well known name (!) with a link to recommended supplier, but I'll be damned if I can find it again... Any pointers please :-)

Dave


DH2

Aha, found it!

It was Bob Turbo in July 2010, he said:

"At the moment if it were me I would contact this company and ask them for a:
3MJT17
and a:
34LJT25

These were the original bearings and if replaced by these then you should have no trouble.
There are cheaper bearings around but these will always be a problem

http://www.ransomeandmarles.co.uk"

So I guess I'll give this a go.

Dave
DH2

Can you let us know how much they cost when you get them?

Graeme
graeme jackson

Dave, that looks like a typical bearing failure when worn. This will start with a very small nick (dirt, a bash to the bearing causing a dent, too little free play) and then the bearing balls will bounce there and it will degrade at a speeding rate.
Alex G Matla

Thanks Alex, you may have a good point there. Either way, it's no good now anyway!

Everyone sitting down for the R&M OEM replacement prices?
34LJT25 is 55.00 each
3MJT17 is 45.00 each
10% off if you are buying a full set of 4 bearings.

Ouch...

Dave
DH2

Hmm, guess that's why everyone stocks carp ones!
Dave O'Neill 2

DH2,

I expect if everyone stocked the proper ones then they would be a lot cheaper due to economies of scale but having said that the face adjustment detail means they would be more expensive than the common garden variety which aren't. Getting any angular contact bearing face adjusted will push the price up quite a bit.
David Billington

these guys claim to sell a set that are properly engineered, based on the MGB tapered + shimmed approach:

http://www.speedwellengineering.com/suspension/tapered-front-wheel-bearing-conversion/


I don't know anyone who has used them, and I don't know if they have got the proper large radius on the inside of the inner bearing, but if so, and if shimmed correctly, they ought to work.

Though, looking at the photo on their website, that radius does not look generous enough, but it is hard to tell. The fact that they didn't mention that radius makes me wonder...



The upside to using the R&M bearings, although they are expensive, is that a proper set of bearings really ought to last the life of the car, so you can think of it as an investment in the future!


Norm
Norm Kerr

Hi Dave
just got a price for the bearing through a company i use in work 3MJT17 14,34LJT25 12 FBJ Bearings made in Japan.
Gary
gary knowles

Hi Gary they sound like equivilents to me? that do not respect the special natures of the original bearings. They will only have same basic dimensions I suspect! Did they tell you what the manufacture and number the bearings were?
Bob Turbo Midget England

Hi Norm I would definately not fit the speedwell kit.

Firstly it would not have the radius that you guys in the USA are so keen on.

Secondly it is just as expensive as angular face adjusted bearings yet requires shimming and a taper arrangement is far less efficient!
Bob Turbo Midget England

I just had this problem with my 1500, a 'noisy bearing' was complained about at its MOT. Pulled the hub and destroyed the bearings bashing them out, other than my damage they looked fine...

Got the 'usual suspects' type bearing kit and ended up just using the grease and the seal, the bearings were useless and made the wheel wobble terribly.

Got some R&M bearings and the quality difference was obvious, as well as having the correct fillet and face adjustment. Put them on and the wheel was rock solid (in a good way!)
RoadWarrior

It's rather alot of money though... yes, an investment in the future, but on a car that's only going to get pretty occasional use...

So what are the alternatives? Are any mods required if I get some face-adjusted bearings? I thought I saw some part codes on my searching travels, which seemed to come out a fair bit cheaper?

Dave
DH2

Have a read at this artical

http://www.mgcars.org.uk/mgcc/midgetreg/Frontwheelbearings.shtml

Im eventually doing the 40 degree angular bearings ... I got them ...in a box with the other front end parts

Something to remember the code numbers in the artical are for pidimite plastic races....but below are the code numbers for the brass races for the same bearings....there a fraction of the cost and are better for the midget enviorment then the pidimite plastic, aka... more for sub zero temps and chemical corrisive and high pressure enviroments

Koyo 7303 BGC 3
Koyo 7205 BGC 3

I got them a year ago...and were $120 for both sides including seals
At IBT....BUT IM Sure you can find them at a better price on ebay


PROP
Prop

Just recently I fitted bearings from Brown and Gammons after checking with them that I would not have any issues with them. After fitting I felt that there was too much play and so I took the car to them for their mechanic to check. To cut a long story short, there was too much play and after a very long discussion with the sales manager and the service manager, they concluded that front wheel bearing replacment is not a diy job (I can't see why not if you have the correct bearings) and that the correct procedure is to fit the bearings, measure the end float, remove one bearing, take the spacer out and have it ground down by the amount of end float (or more), making sure that its surfaces are still parallel and then refit. If the bearing is too tight you should remove one race again and fit a shim from an MGB front bearing. Keep adding or removing shims until you have the correct play.
I explained to them that you cannot remove the bearing without splitting the two halves rendering it unserviceable. They seemed to think you could!
Dave
Dave Brown

Dave a common enough idea when applied to tapered roller bearings. Not a lot of mechanics have seen the ball type thrust bearings in many years and are not familiar with how to service them or set them up properly. As for their method of attaing a good "fit" I'd be highly suspicious that it would work. Unlike taperd roller bearings which still have a proper working alignment when "tight" a thrust type ball bearing can be over tightened and that will push the contact area to the side instead of on the inside which will result in poor wear and early failure. That's the reason that you must have a pecision face adjusted bearing and use the original spacer between the two bearings, to insure that the bearing preload is absolutely correct, not overly tight or loose.
B Young

Yes B, I know.
I cut my story down quite a bit. I stood and argued with them for some time that they had sold me the wrong bearings and that they should warn every one who asked for their bearings of the issues with them.
I still have an issue with B & G over them and I am sure that I will get my money back eventually.
There are so many of these incorrect bearings being sold know that if the correct parts were ordered the price would come down to something that is affordable.
The labour costs of fitting, measuring, grinding, fitting... repeat until done, must be huge if one pays a garage to do the job.
Dave
Dave Brown

You are right Dave. The technique used by B and G is the one I have used before when the original bearings became old stock and unobtainable a number of years ago. The technique simply does what the face adjusted bearings do and that is to ensure the races are alighned.

The problem is that also the bearings supplied by B and G and every other mg specialist also do not have the correct radius ground into the inner surface of the inner race and thus can effectively not sit correctly on the stub axle. Therefore they suffer from 2 failure points.

I personally do not have a problem with the inner radius and am therefore quiet happy to purchase the modern 40 degree angular contact face adjusted bearings, again far supperior to the cheap equivilents offered by specialists and will fit without modification and also no play in the wheel which is by far and above our major MOT problem. Although if NOS originals can be purchased they will also fit perfectly as described above.
Bob Turbo Midget England

OK, so does anyone have definitive part numbers for these 40-degree face adjusted ones that appear to work without any play? I'm happy to spend on quality parts, but am struggling to justify 200 for the OEM parts.

Dave
DH2

Yes I have the numbers but they will cost about the same as the originals because they are designed to do the job!!

You will need a new oil seal (Payen NA301) and an inner and outer bearing that are

NSK nos 7303BEAT85SUN 7205BEAT85SUN

or in SKF no's 7303BECBP 7205BECBP
Bob Turbo Midget England

Thanks Bob.
I've already got new oil seals - hope I can knock them back out again without damaging them and having to buy them again.
I'll go sniff out some prices.

Dave
DH2

Bob and Dave,

Those part numbers have the pidimite plastic races ... Made for corrision, super cold, and high pressure

Cross referance them to the brass races, the brass is way better suited for our cars....and there easily a 1/3 the cost

See my above post

Prop
Prop

Prop please stop talking b0llocks please, please please, this is a serious subject.


However for your information the bearings identified do have the "plastic" cages as opposed to brass. The brass caged bearings are MORE expensive and are generally used in applications where temperatures are expected to be in the region of 100 degrees C plus. (That is 212 degrees F for you yanks!!)

By the way at these temperatures lubrication is a major consideration. Anyway Dave the information I have given to you is from the mouth of the applications director of NSK previously RHP who made the original bearings for BMC/Leyland and was the person who originally identified why the new bearings supplied by MG specialists such as B and G do not fit correctly!!!
Robert (Bob) Midget Turbo

Has anyone bought any of the standard aftermarket bearings available these days and checked the inner bearing inner radius to see if it correct for the spridget or that of a common industry standard bearing. My car has been off the road since 1997 and most likely had its last front wheel bearing change in 1995 or 1996. I used to change them every year or other year in those days as the play seemed excessive prior to MOT and they were cheap and easy to change. I would get them from my local factor and they would be QH. Last year I checked the inner bearing inner radius and it was the correct large radius and I posted a pic. I'll have another look this weekend and maybe pull the inner bearing and see if it has any designation on it to indicate who made it at the time. QH were supplying bearings with the correct critical radius but maybe not quite as tight a tolerance on the face adjustment. A bit loose being better than too tight.
David Billington

David Brown,

Reading your post earlier I thought your mechanics were talking out of their ar*e but it did make me think about whether separable angular contact bearings were available and a quick search indicates that they are. The quick search did seem to reveal that angular contact bearings are commonly available in 15, 30 and 40 degree variants and that some 15 degree variants are available in separable formats. One item indicated that separable bearings might be required in some applications where dynamic balancing of the supported assembly was required and removal of the inner part of the bearing was required. Whether these would be suitable for the spridget I don't know but I would expect pricing might lead one back to the proper bearing for the job if one enquired.
David Billington

Sorry robert

But your not calling me bollocks... BuTt rather a 24 Year vetrenern engineer employed by IBT That specializes in bearing applications in the local area of agreiculture and industry

The info im posting is not my research .... Its all IBT and there enginering staff...his name is chip ???? I can post his phone number if you would like to ream him out for being an idiot.


Prop
Prop

Hi guys,
I am the guy that found the source for the R&M ball bearings. Paid my money and they fit like they should. A good thing too because by that time I am sure everyone wished I would just go away.

Bill Young has a good roller bearing solution. I found the 07097/30303 taper bearing combination to give the correct position of the rotor.

Norm Kerr also has some answers.

My findings; http://smithtr6.com/bearings.htm


tomshobby

This thread was discussed between 24/08/2011 and 27/08/2011

MG Midget and Sprite Technical index

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