wheel bearing pre load

[ian.johnwilliams@tiscali.]

Just in process of front wheel bearing change, just a little confused with peoples opinions on adjustment. Some are saying bearings require a running clearance and some say toyota recommend bearings are pre loaded, can someone out there explain to me what advantages are there in pre loading?

[NiftyNev]

Preloading is used to ensure the bearings are properly seated. This is done while spinning the hub forward and backward a few times as you tighten the retaining nut. They should be then backed off and then retightened to remove almost all endplay. Technically, final adjustment should be done with a dial gauge and the bearing endfloat set to the bearing manufacturer specs. Very few actually do it this way though. Bearings that are too loose or too tight will not last anywhere near as long as a bearing with proper adjustment. A little loose is better than too tight because a tight bearing will fail very quickly.

Check this link for some detailed info on bearings -

http://www.timken.com/industries/aut...s/techtips.asp

Nev

[M35A2]

Always pre load the hub bearings. Packing them with grease and refitting them will require them to be preloaded so that they seat properly.

As NiftyNev has said.

Spin the wheel and tighten the bearings so that the wheel hardly turns or is very tight, spin it some more then slacken off the hub nut so that the wheels spin freely. Then retighten so that the wheel doesn't spin as much, but still spins freely. When the wheel is loose, if you hold the top and bottom of the tyre and push and pull in an in and out manner (ie, push the top towards the wheelarch and pull the bottom out towards you) quite quickly. You should feel a little bit of movement and may hear it clicking or knocking. When the bearing has been adjusted properly all this slack is taken out so you can't feel it move or hear it click, but the wheel will still spin freely.


Take the truck out for a test drive for a good ten miles or so and keep stopping and feel the hubs for heat. if the bearings are too tight the hubs will get hot.

Hope this helps.

[ian.johnwilliams@tiscali.]

Cheers Nifty Nev and M35A2,Just found this information on toyota surf maintenance site,,

( The preload on the outer bearing has to be set. To do so, using either a 54mm or 2 1/8" socket and a torque wrench, torque the adjusting nut to 43 ft. lbs. After setting it to this torque, spin the rotor/hub assembly each direction several times, then back off on the adjusting nut until you can turn it by hand. Then set the torque wrench to 18 ft. lbs. and torque the adjusting nut.
Toyota recommends that the rotor preload should be set to 12.6 ft. lbs. This can be accomplished with a spring gauge, or a fish scale.)

Taken note of what you have both said and will be doing as you suggest, just on reading this information seems like 12.6ft lbs pre load on the bearing leaves no clearances???

Would appreciate your views on this re-torqueing back to 18ft lbs. Also when you tighten up the locking nut it does tend to push in the adjusting nut a bit, guess thats play in the threads, how will that effect the end result

[M35A2]

When i rebuilt my Defender axles I tightened the hub nut as I mentioned in the above thread, and retightened it HAND tight, then just a fraction more using a hub spanner. This got the required torque.

Tightening the outer nut will take up a little, that's why you need to road test to see if the hubs get hot.

[ian.johnwilliams@tiscali.]

M35A2, Thanks have done it way you have suggested, been out for run in truck and have been checking wheel hubs, all looks good so far, thanks once again

[M35A2]

M35A2, Thanks have done it way you have suggested, been out for run in truck and have been checking wheel hubs, all looks good so far, thanks once again

No worries mate.

As long as you tightened the bearings right up, then slackened them off, then tightened them hand tight and a fraction more and there is no play in the bearing then you are sorted.

I need to do my fronts as they have quite a bit of play in them, but after doing that head I'm going to leave it till another time. I'm sick of working on the thing at the mo.

Glad you got it sorted.