Pre-load of taper-rollers

[colin hawesParticipant @colinhawes85982]

My 1947 1 1/2 litre jag front wheel bearing was ruined by an M.O.T tester's insistence that he would not pass it unless I eliminated the recommended bearing clearance on the front wheel. I had to go about ten miles to get home.The taper roller bearing turned blue. So it's not always correct to pre load this type of bearing. Colin

[Howard LewisParticipant @howardlewis46836]

Pre loading taper roller bearings in a wheel hub is recipe for disaster.

The epic example was the fatality caused by a dealership assuming that the new mode, like its predecessor, l still used ball races, where the new model used taper rollers. They tightened the nut to the torque for the ball races and when the hub seized at speed, the car went out of control, killing the driver.

Our Skoda 110R improved when I slackened the front hub bearings to give 0.002 – 004" end float. (The workshop manual called for end float, but initially, there was none!) The steering lightened, and self centred after that adjustment. Another improved in the same way as well, given the same treatment.

Renaults of that time specified 0.002" – 0.004" endfloat. For many years, Leyland had specified end float for taper roller front hub bearings. The vehicles in my fleet covered about 60K miles each year, but we never had a failure.

Pinion bearings are preloaded. The workshop manual advised the practice on Ford Anglias, (and presumably Cortinas as well) post 1959, was to install a new crushable spacer between the bearings and then to tighten the nut until a spring balance, on the end of a string around the diff casing gave the required reading.

This suggests that the preload was pretty small, just enough to produce a small drag torque.

Lathe Headstock bearing are often lightly preloaded, to ensure accuracy of alignment.

Hope that some of this helps

Howard

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