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MG MGB Technical - Front wheel bearings

Has anyone done a conversion from the standard setup to use tapered roller bearings. I have trouble setting up the bearings to eliminate 'wobble' everything is new including the actual wire wheel hubs and the wheels, but I still have a small amount of play that the inspector does not like. This is for our WOF...similar to MOT in the UK .I do get a pass but only because I know the guy.I've tried the archives but didn't find gold.
R F Murray

Take the workshop manual to show the guy - it is DESIGNED to have 2 to 4 thou endfloat!

Chris at Octarine Services

And all MGB already have tapered rollers!

FRM
Fletcher R Millmore

Yes silly me...I was having a Senior moment. I've had the wretched tapered bearings out so many times, I was told today about the built in tolerance.
R F Murray

"I was told today about the built in tolerance"

If you mean the 2 to 4 thou end-float Fletcher mentioned this in *not* built in, it has to be set manually using shims between the spacer tube and the outer bearing.
Paul Hunt 2010

Think that was Chris mentioned the end float.
Do you have a shop manual?
The set up procedure is detailed well, and getting it right matters. Too loose gives sloppy steering, poor and variable brake pedal travel, and beats the bearings to death - and you get to start over. Too tight kills the bearings and you get to start over. Done right they last pretty well forever with occasional regreasing.

FRM
Fletcher R Millmore

I have the original Timken front wheel bearings in my '67. I've cleaned and repacked them with grease 3 times in the 38 years that I've owned the car and they look like new. RAY
rjm RAY

Helo RF,
sounds like you have not got the wheel bearings shimmed properly. You have to reshimm when you put new bearings in. It's not hard to do and you don't need dial gauges ets, obviously the latter will save time, but they are not necessary.
Here is a link to Pauls excellent site.

http://www.mgb-stuff.org.uk/hammerframe.htm

you may need to scroll down a little way.

MGB's are unusual in that they have a large inner spacer and some shims that hold the inner and the outer bearing apart which allows you to exactly set the end float on the bearings. A really good idea but not done on modern cars I suspect because its too time consuming to set up on a production line. And they don;t care if their bearings fail after only ten years.

Essentially there are three shim sizes and you stack various combinations of these three to get different thickness's (eg one of the thickest plus three of the thinnest etc). You swap various shim stacks until the bearings just start to bind when you tighten up the wheel nut.(careful don't damage the bearings) then substitute the next size up shim stack which will allow the wheel to spin freely with the wheel nut done up tight. Then you should grease the bearings. You do the set up with them clean and dry. It took me about half an hour one side and 10 minutes the other. It's easier than it sounds because a sensible guess will get you almost there.
P.N. Sherman

http://www.mgb-stuff.org.uk/wn_suspensionframe.htm is easier, then click on 'Front Bearing End-float'.
Paul Hunt 2010

The B's bearing setup is really one that works very well. I've seen quite a few bearings that have failed and destroyed the spindle because the inner race spun on the it. This is prevented on the B because the 2 inner races are locked together by the spacer collar and shims which are in turn locked in place by 80 lbs. of torque. Just about all pinion bearings use this same design. RAY
rjm RAY

See here: http://www.youtube.com/watch?v=RJYIXZtnIiw
Steve S

I've always wondered why the British cars used this design. American cars and trucks, even tractors and trailers have never used it and if greased properly, I've never heard of a wheel coming off or freezing up. I grew up in a racing family and all of our cars and for that matter, everyone else's did not use the method used on British cars. I'm not downing it mind you, I just can't for the life of me see the justification in it. I know a couple of fellows here that have MGBs and they installed their front hubs using the American method and years later they've had no issues. I will say my wifes 72 "B" that I restored, has the British set up with spacers and shims. PJ
Paul Jennings

Steve...thankyou .I've just watched the 'you tube' thing you posted. Great stuff...will get onto it soon. Renton
R F Murray

I *have* heard of bearings spinning the half-shaft and seizing to them. There seems no point in not doing it other than the factory did it, other than laziness. Unlike insisting there should be a pre-load on them intead of an end-float, which is just perverse.
Paul Hunt 2010

I've reviewed John Twists video on YouTube and I have a great deal of respect for John's knowledge and integrity. I do however have a slight disagreement when he talks about torquing the axle nut to 60 ft/lbs. and ends the discussion there. There's more to this process.

His discussion didn't focus enough on the fact that the axle nut is a castle nut with a cotter pin. There's a specific reason for the castellated nut. One must first "pre-load" the bearings using 60 ft/lbs., spin the wheel, and then back off slightly to align the cotter pin through the castellated nut and the corresponding hole in the axle. When you do this you have effectively reduced the previously set torque value, i.e., 60 ft/lbs to somewhere around 30-45 ft/lbs, which is more than adequate. I prefer 20-25 ft/lbs. with very little end play. If, at this time, one notices too much end play, more than the thickness of a piece of paper (.003") then you may have to add a .005" shim.

I have had a wheel almost come off from having the axle nut and bearings on too tight (60-75 ft/lbs). The process of pre-loading the bearings and then backing off to achieve the alignment of the cotter pin to the hole in the axle has been around for a long time. The good ol' American procedure is the very best method, even for little british cars.

Finally, the inner bearings do get dry. Both bearings can get hot enough to boil the grease (soap mixed with oil). When the wheel cools, the residual grease accumulates on the inner bearing and one can infer that the grease had been there all along. I mean, it's there when you disassemble the bloody thing right?
R Murray

R Murray Washington USA;

I have not seen JTwist's video, however, I reckon it is probably correct, as is most of the discussion above. And there is a wondrous thing called "MGB Workshop Manual".

All of which indicates that you haven't got a clue. Read the stuff and do it correctly; if it's too hard for you to understand, get somebody else to do it.

The "The good ol' American procedure is the very best method" is OK - IF the thing was designed for that method, and IF SOME MORON DOESN'T SCREW IT UP. In this "American" procedure, the nut torque is always finally zero, so that the bearing is not preloaded. Allowing bearings to float and slowly or intermittently rotate on the spindle is way of distributing wear on a bearing, but it sacrifices rigidity and fatigue resistance of the spindle.

The MG system is an engineering nicety evidently beyond you, and calls for a different procedure - that'd be the one in the WSM. Locking the bearing in place sacrifices some bearing wear life, in exchange for rigidity and increased fatigue strength. At the bearing loadings on these cars, life is not much of an issue, especially if the bearings are removed for greasing and rotated on the spindle a bit once in a while; all in all, I'd rather replace a bearing occasionally than break a spindle. The same "IF" applies.

Bearings seize because they are too tight, not lubricated, or from fatigue/alignment failure - which may be caused by running too loose. Locking the bearing to the spindle may prevent the bearing spinning on the spindle when it fails, or it may just destroy more parts. In either case, it is not unknown for spindles to shear off entirely.

FRM
Fletcher R Millmore

The only time you pre-load the bearings is when you have replaced them and tighten the nut *without* shims to seat the bearings fully, and then you only torque it up until the bearings start binding. Properly shimmed, you torque it up to 40 ft lb, then continue to tighten until the first of the two split-pin holes lines up with castellations, which should always be before the maximum torque of 70 ft lb. If John Twist really does say "just torque it up to 60 ft lb and leave it" then he is wrong. Neither do you torque it until they bind then back it off until a split-pin holes lines up and leave it.
Paul Hunt 2010

Mr. Millmore of PA

You can skip the bullying and name calling Mr. Millmore. Try to make your comments friendly and constructive.

I hear tell folks in Pennsylvania are friendly and courteous.

I say ol' chap, view John Twist's video on this subject in YouTube.

Thanks,
R Murray
R Murray

John Twist:

Front Wheel Bearings.

http://www.youtube.com/watch?v=RJYIXZtnIiw

R Murray

Like many enquirers and possibly respondents, I am a "keen amateur", who values the advice of "seasoned professionals" on the various Bulletin Boards. FR, you have responded to at least one query of mine before, and I'm grateful - you probably have 50 years' experience, and I don't. I was therefore unhappy to read your intemperate remarks directed to R.Murray of Washington. The whole point of these BBS threads is surely to enable keen amateurs to ask questions, and occasionally to offer input, without fear of being ridiculed by those who have "been there, done that". You sir have done our worldwide fraternity no favours by venting your spleen at what seemed to be a perfectly reasonable comment, and, for me at least, a useful thread.
J.P. Hall

Whilst Twist is correct in saying tightening the bearings onto the spacer results in a stronger axle, his is *not* correct when he says they should be loose enough to turn freely but not have any in and out movement, the Workshop manual specifically calls for .002" to .004" end float. However later on he corerct this by saying there shouldn't be too much 'tunk'. He is corterct in saying that at 60 ft lb the end-float is correct, but he misses out the correct final tightening process which is to tighten to 40, then the next split pin hole. This could any up anywhere between 40 and 70.

Neither is Mr Murray correct when he says "If, at this time, one notices too much end play, more than the thickness of a piece of paper (.003") then you may have to add a .005" shim." Adding shims *increases* end-float/free play, as Twist says "if it's too tight you need more shims", or more correctly more shim thickness. You don't simply add or remove one .005", you have to juggle with .003", .005" and .010" to vary it by .001, .002, .003 etc. until you get the correct end-float.

It's actually easier to do it by ear than with a dial gauge I suspect, as with a dial gauge you would have to pull the hub in and out keeping it exactly parallel to the spindle or you will get inaccurate readings. Much easier to get two set of shims .001" apart that produce no and just perceptible play, then add a .003" to the lower set.
Paul Hunt 2010

Mr. Hunt:
Thanks for the correction. You are right of course. This made more sense when I examined the cross sectional detail further. I've included the X-Section of the front axle which is similar to the rear configuration.

The most confusing aspect of all this is the nomenclature between British and US English. A Bearing Spacer can be an "Oil Seal Collar" and a tabbed flat washer can be an "Axle Shaft Collar"; a Propeller shaft has been misidentified as an axle shaft in a couple of places in the Complete Official MGB WSM by Robt Bentley Ltd.

In any event, if you examine the X-Section illustration that I have uploaded, turn your attention to the machined shoulder on the axle shaft. Note the space between the flat tabbed washer contacting the ext. face of the outer bearing race. If there were no shims installed, that would move the flat washer (Axle Shaft Collar") up against the shoulder on the axle shaft and attempting to provide proper torque values to the axle nut and to the bearings would be difficult.

One last point: notice how the lower inner raceway of the outer bearing extends beyond the machined shoulder of the axle shaft. (Looks like the thickness of 2 sheets of paper, i.e., .005"-.006")

Finally, I would like to share with you one last anecdotal comment on all of this. (It is the MG "Experience isn't it?) About 35 years ago I had a Ford van with almost the identical configuration of the front axle as the MGB. I wanted to be sure to get it torqued properly so I tightened the axle nut to 60-70 ft. lbs. I drove the van 15 miles before the wheel was about to come off. I limped to the repair shop where this ol' mechanic noticed that I had successfully welded the bearing raceways to the axle. He said "you young fellers do this all the time! You get things too damn tight!"
Safety Fast my friends.


R Murray

Ooppps again. It is the MG ENTHUSIASTS BBS. (The one mentioned is another great MG Web Site.) RM
R Murray

"You can skip the bullying and name calling Mr. Millmore. Try to make your comments friendly and constructive."

I have been lurking here for many, many years, & I can assure you that when Paul Hunt or Fletcher Millmore post, a wise person will learn something, regardless of delivery.
Carl Floyd

The clearance between the tabbed washer and the shoulder on the axle shaft is deeper than the thickness of any likely shim set. It's that extra clearance that allows tightening the nut with no shims fitted to fully seat the bearing outers in the hub when the bearings have been replaced, i.e. applying force through the rollers.

If you have pre-load instead of end-float on an MGB then 60ft lb *will* likely weld or melt the bearings. I don't see the point you are making, you got it wrong, and paid the price. If you fit no shims at all and have no torque on the nut, but get the correct end-float, you may still weld the bearings, but this time the inners to the axle shaft.
Paul Hunt 2010

R, what type of Ford Van were you working on that used a "spacer-shim" system? As the time period you are talking about had me working on more then a few Ford vans and I can't remember one.All the rear wheel drive Fords used a zero preload system with no spacers or shims. RIC
RIC LLOYD

This thread was discussed between 17/03/2010 and 20/04/2010

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