Fitting new front hub bearings

[bmcecosse]

Can't agree! The thrust is being taken by the other bearing! As long as they OPPOSE each other - one of them is available to take the thrust in each direction. But I can see I'm not going to convince any of you - so I give up.

[RobThomas]

I can see I'm not going to convince any of you - so I give up

Just build the hubs as BMC intended and it will be fine.

[rayofleamington]

Can't agree! The thrust is being taken by the other bearing! As long as they OPPOSE each other - one of them is available to take the thrust in each direction. But I can see I'm not going to convince any of you - so I give up

The original design bearings are intended to have a clamp load path (taking the load from the nut) and this is the basis of how they work. getting them the wrong way round will load the side that's not intended to take permanent load.

Putting the bearings the wrong way round might be ok to start with, as it'll take a little while before they are damaged and fall apart, leaving a DANGEROUS situation. How long would that take? I wouldn't want to find out!!
Therefore don't bother taking the risk and install correctly.

[ampwhu]

would somebody translate this into laymens terms please... i am a practical man.

the bearings i have, have a tapered build. one side (smaller bearing) has a plastic ring one side. this is the outer bearing i think? which way round does it go?

[IslipMinor]

Please see the attached photo of the inner and outer front hub bearings, showing the 'thrust' and 'non-thrust' faces of each bearing. The larger bearing is the inner bearing in the hub, and the smaller one the outer bearing:
[frame][/frame]
The bearings in the upper part of the photo show the 'thrust' side of the bearing. It is this face that goes into the hub first and locates on the inside step, so that the 2 'thrust' sides of the bearing face each other in the hub. The key thing to look for is the manufacturer's details and part numbers are on the 'thrust' face, and on older bearings the word 'THRUST' was also included as well.

The lower part of the photo shows the faces that are visible when looking in from each end of the assembled hub. There are variations on what you can see of the balls and the cage, depending on the manufacturer. Also the cage itself can be made from steel or a resin. The key thing to look for here is the thinner outer ring of the outer race - it is the start of the taper that allows the bearing to be assembled, but also allows the bearing to 'fall apart' if the inner race of the inner bearing is tight on the stub axle.

[IslipMinor]

Best effort with with MS Paint and Photoshop to show how the hub will fall off if the bearings are fitted the wrong way round.

If I can find a spare spacer, I will build up an upright and hub, with the bearings wrongly fitted, and then show how it will come apart - but not fitted to the car! At the moment cannot find a spare spacer.
[frame][/frame]

[autolycus]

Excellent diagrams and photos, and a very clear and totally convincing explanation - many thanks for taking the trouble!

Kevin

[RobThomas]

Darn! You're good with computer drawing things. Took me 2 days to do one simple diagram on CAD.

Excellent explaination and pic! 10 out of 10. Gold star!



PS It's gone quiet on here. Think he's crashed?

[IslipMinor]

The original CAD drawing is not mine - I found it on the net and just used it as the basis for showing the standard bearing assembly and then used MS Paint to modify it to show the bearings fitted the wrong way round and falling apart!

No, will not fit them like that, ever!!

[RobThomas]

Glad to hear that!

[bmcecosse]

He's been away driving steam engines 5 days out of the last 6 and has only been 'speed reading' the threads. The diagrams are absolutely excellent, especially for someone (me) who can't draw a stick-man - I'm just not convinced they show real life conditions. But if in doubt - please don't take chances, and do fit them as per the Manual. I've never had any problems with (Minor) front hubs - and so I have never had to dismantle one. Maybe one day I will take a hub to bits - and see for myself. I have to say the taper roller bearing option does sound interesting and a bit more robust!

[Mr Don]

A final note to this.
Some cheap bearing pullers made this job much easier.