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MG MGB Technical - Front hub bearings

I am about to rebuild the front end on an MGB. This has tapered bearings (unlike my MGA)

How should the tapers be oriented - it's not clear from the workshop manual I have.

Options appear to be:

1. Both tapers facing inwards to car
2. Both Tapers facing outwards from car
3. Tapers facing each other inside hub
4. Tapers facing apart from each other inside hub

I know this is critical to setting up the preload on the bearings - an A is so much simpler in this respect!

Thanks
Dominic
dominic clancy

Hello Dominic,


The front end bearing setup is titled "O" setup. In attachement please find a scan describing each component
installation.

Guy RENOU

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

John Twist tells you all you need to know!
RoadWarrior

Thanks gents

Guy, I have that picture, but couldn't figure out how the bearings were oriented in the picture.

The Twist video tells me all I need, except I notice that he doesn't mention the vital oil seal at all.
dominic clancy

A few tips:

- use a seal....

- don't grease the bearings until you have got the end-float sorted

- torque it up tight to seat the bearings with no shims, otherwise you'll chase your tail all day

- there's an order to things which would have ruined Mr Twist's natty (but flawed) description... the rear oil seal goes in after the inner ball race, and the spacer will not go through the hole in the inner ball race (obviously) ... so you have to put the spacer in the hub, then put the inner ball race in place, then tap in the oil seal before you can sit the hub onto the axle

- and you need to put the brake disc on the hub before you put the hub on the axle!

HTH

Neil
Neil22

Dominic,

The front hub bearings do not have preload as you stated in your first post. They have a running clearance of 0.002 - 0.004 inches.

Mick
M F Anderson

Yes .002 - .004 end clearance is correct but this must be achieved with the hub nut at 60lb/ft using shims to get the clearance correct. I was always taught that the starting point for the shim pack is 1mm + .010" which seems a strange combination but in practice this works out pretty well. As Neil states don't grease the bearings until you have got the clearance correct as it is much easier to detect the clearance in dry bearings. Once you have got this correct dismantle the hub pack with grease, then refit and torque it up. Job done.
Iain MacKintosh

Pack the bearings, but not the space between them.

n

Neil22

Perhaps I misread, but I would strongly advise against seating the bearing races by smashing the bearings into them. If the races aren't set already then they weren't installed properly on the bench. Mashing the bearings by torquing the nut down on them without shims in place can damage both the bearings and the races by brinelling them.
Steve S

My learning is just as Steve says, however: "...tighten the nut until the bearings bind, This will pull the outer races fully against their locating flanges inside the hub." - WSM I've read the same in other books, probably emanating from Timken themselves way back.
I suppose this to be one more of those things that depends on mechanical feel to not screw up. It takes a lot to Brinell a bearing like this - hammering or a big press. I do it as the book says and have carefully examined bearings so done, up to the recommended max of 70lbft torque. Not a problem. If you get Brinelling, get better bearings!

note: "Brinell" is a man's name, and the hardness test that gives rise to the term we use was developed by him. I think we should capitalize it and spell it correctly, and yes, I have to look it up frequently.

FRM
Fletcher R Millmore

Agree fully with FRM. Torquing up the bearings to seat them properly never did any good bearing any harm and it is the only way to make sure that they are fully seated before going to the bother of setting the shimpack.
Iain MacKintosh

and with the taper, you'll hardly be putting any load on the track anyway...

Neil
Neil22

Iain, I wouldn't say never as I've seen the damage first hand. I agree that the bearing used in an MGB hub are very tough and would require a lot of force to become visually damaged. My point however is that the race should be pressed in properly BEFORE installing the hub. If you can move the race by simply tightening the nut down on the bearing then there was not nearly enough force used to press the race in the first place. Aside from that, damage is not always visually obvious!

Neil, without shims in place, all of the force will be put on the bearing and races, not on the taper. The shims are what transfer the load to the tapered spacer, if that's what you were referring to.
Steve S

Hi Neil

I knew that the spacer needs to go in there, but thanks for the reminder that it doesn't fit thru the bearing race.

I always press bearings in using a vice and a suitable drift that only contacts the outer race, so that the bearings themselves are never under any force. I press seals in using a vice and a drift so that the seal is pushed in solidly and evenly all the way home.

For the B and A rear hubs I have a metal tube and a metal disc that are turned down to the correct size. Makes it a 2 minute job to install everything
dominic clancy

Dominic,

Best method to be sure not to pit the rollers races contact surfaces. I used the manual method without damages, but I dislike it. Sorry not to help you more with my pic.
Guy RENOU

What I meant is that by applying a torque to the nut you are applying an axial force, very little of which is seen by the bearing running surfaces due to the taper/angle. In my younger days I would have been able to calculate exactly how much... If there was no taper (an axial bearing) then the running surfaces would see none of the force.

Don't be too worried about the strength bearings - after all, the whole weight of the car normally acts on them, as do the shock loads going into the suspension...

N
Neil22

This thread was discussed between 21/02/2010 and 28/02/2010

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