Re: Front wheel bearing pre-load

Posted by DJ.Voyce on May 25, 1998 at 02:35:25

In Reply to: Front wheel bearing
posted by Jim R on May 24, 1998 at 07:21:42

G'Day Jim,
To add my two cents worth I've got to go with Steve on this one. There was a reply to a letter in the technical column of one of the more recent "Restorers" on adjusting front wheel bearings which stated that the nut should be backed off until a slight clunk could be heard when checking the hub for end float. This is totally incorrect as any dual taper-roller bearing set up has to have a certain amount of pre-load to prevent it destroying itself by the shock loadingsset up if the bearing is allowed to to float around off & on its contact surfaces. This can be likened to walking next to a wall with your head rubbing on it, when you get to the end you might have a roastie on your ear at worst, but walk down the same wall banging your head on it & you're probably going to need some sort of medication (or a man in a white coat if anyone's watching you).
There are many different ways of setting preloads & most good tradesmen are able to carry out this operation by feel, on all taper bearings including differential, pinion, steering box or in your particular case, wheel bearings.
To add to Steve's method, let me try & explain in simple term the way I was taught & have been using for years with no problems. First tighten the axle nut up tight, this will push the bearing cups firmly onto their respective registers in case they may not have been knocked home completely when fitted. Back off the axle nut then re-tighten gently in the following manner, hold the wrench as close to the nut as possible with your thumb around the open end of the wrench or back of the ring depending which type you're using, sort of like tightening a screw-on peanut butter jar lid, & line up the nearest cotter pin slot on the castellated nut. This way you'll be sure of not over-tightening it (unless you've got arms like Arnold Schwartzenegger). Remember that even a little pre-load is preferable to none at all. A simple check on your handywork can be made by taking a broad bladed screwdriver & inserting it between the edge of the washer fitted behind the bearing, & the hub, then twisting it so that the blade is trying to push the washer away from the inside of the hub. Then move the screwdriver directly opposite & twist against the washer from this side. If you've got the loading on the nut right the washer should just be able to move slightly behind the bearing without having to actually lever it from side to side. If you can't get the cotter pin lined up without the pre-load being too much, or too little, it may be necessary to file or grind a little off the back of the nut until you can.
A little time & effort spent here will ensure maximum life from your bearings & as Steve pointed out, eliminate one more cause of annoying shimmy.
Regardz
DJ.
OutOfAfrica A's

: I'm in the process of replaceing my front wheel bearings. When i took the front drum and hub assembly off i noticed there was no front inner dust seal holding the larger inner bearing into the hub. (The guy i bought the car from had done some brake work on the car). My question is, is there supposed to be an inner dust seal holding the larger inner bearings in the hub? and if so does it sit in flush in the back of the hubor stick up a little. Also which side of the dust seal goes in against the bearing.
: Thank you in advance for your time in answering.

Follow Ups:
Amen to that - Bob Carabbio May 25, 1998 at 21:33:11(0)

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