DON'T ASSUME ALL THE AFTERMARKET KITS FIT YOUR HUBS CORRECTLY BY JUST BOLTING THEM IN, SOME `NON-TIMKEN' ONES DO NOT.
I HAVE REPLACED A FEW FRONT BEARINGS FITTED BY A MINI SHOP THAT DIDN'T CHECK PRELOAD. THE BEARINGS FAILED WITHIN A COUPLE OF WEEKS DUE TO EXCESSIVE PRELOAD.
I STRESS THESE WERE NOT GENUINE TIMKEN BEARING KITS, BUT AFTERMARKET ONES.

Assembly of Timken style tapered roller bearings to Mini front hubs (both drum and disc type)
NOTE- special equipment is needed- if you don’t have it, take it to somebody who does.

1. Clean the hubs out, check for undue wear on the centre web from bearing cups spinning. If bad, find another hub. Fit the new cups, ensuring they seat against the web. If slightly loose use Loctite 609 on the outside of the cups.
2. Check the new bearings are a neat sliding fit on the C/V (are on drive flange, with drum type). Remove any burrs with 220 wet/dry paper. If the C/V or drive flange is grooved, find another.
3. Assemble the bearings, spacer, C/V and drive flange without the seals and without grease.
4. Fit the nut and washer, torque up to 60lb/ft for drum C/Vs and 150lb/ft for disc C/Vs.
5. Rotate the drive flange by gripping it with finger and thumb, if it feels slightly tight but spins without any jerkiness that is OK. If it is tight and jerky when turned slowly, the spacer is too short. If it is loose and can be rocked even slightly, the spacer is too long.
6. If there is looseness (the usual problem if any) set up a dial gauge on a magnetic base or bracket, aligned with the end of the C/V. Push and pull the CV to establish end float present. Then machine or surface grind the spacer by (end float +.001”), this will give .001” preload when assembled. eg if it has .005” end float, grind .006” off. The spacer must be accurately machined parallel, do not try and do it by filing or using an angle grinder. Reassemble and check again rotation again.
7. If the bearings are tight and jerky you will need to find or make a spacer that is too wide, then assemble it, and proceed as in [6] above.
8. When you are happy with the rotation torque, disassemble, grease the bearings, fit the seals and reassemble.

Properly done, the tapered rollers last for a long time. My car had them replaced by me about 85,000 miles ago using this method, they are still fine.


<edit> Note that torque required on hub nut is determined by C/V type, NOT the bearing type fitted.
Disc brake Cooper 997 and 998 use drum type C/Vs, so these are torqued up to 60lb/ft, NOT 150.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Matt The Mini Man had this to add - to grease or not to grease, is up to you

Grease em first by all means, but I leave both seals out when checking preload, as they add quite a bit of drag when new. No seals gives you a better feel for what's happening. Easy to tap them in when you are happy, but wipe the swivel hub with thinners so the recess isn't greasy. Then, they stay in, not slip back out.

I do all this work on the bench, not on the car.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.