Simplified Wheel Bearing Installation
As of:  14 October  2003 

        Many of you have worried and worked for hours trying to get the right combination of shims on the front wheel bearing spacers of your MG.  Just when you think you have it nailed, you find that the cotter pin hole can't be lined up when the nut is torqued properly. Well, all your labors were for nothing. Why does your MG, and maybe some other British cars, have the spacer and shims when billions of other cars with front wheel bearings do not? The answer is simple. You don't need them. You could tie the spacers on a string and drag them around behind you and they'd do just as much good as they do in that hub.

        Nearly all other cars in the world have wheel bearing configurations exactly like your MG, except, they have no spacer or shims. They say the shims are for setting the bearing "float", but you get the same float with or without the shims. With the shims you work to a torque spec, without them you don't.
        To be in step with the rest of the world leave the spacer and shims out. Tighten the nut good and snug, turn the wheel a half turn or so, loosen the nut, and turn it right lightly until you feel it make contact. Wiggle the wheel and if you feel any play or looseness tweak the nut a little tighter until that play is gone. If the cotter pin hole doesn't line up back off to the first cut in the nut that will. Some spindles have two cotter pin holes, one vertical and one horizontal. Catch the closest one you can and insert the pin.
        The reason for tightening the nut and turning the wheel the first time is to press any excess grease from between the rollers and the cup. When you back the nut off and re-set it lightly there will be a slight float, but you won't feel it. Sometimes you can after the car has been driven a few miles. Most cars have no cuts on the nut, but have a "tin" nut with cuts for the cotter pin that slips over the "real" nut. You have infinite adjustment with them. My MGB is the only car I ever worked on that had shims in there. No other car, trailer, tractor, or anything else had them, nor needs them, and the bearing, spindle, and hub configuration is the same as an MGB. The only cars I ever worked on that required a bearing float that you could feel were '40s and early '50s Chevy's that had ball bearing front wheel bearings. The shims in an MGB are overkill, I've never worked on even an airplane that had them.
        Those bearings are going to do exactly the same thing with or without the shims. Those cones don't float on the spindle either way, the angles on the bearings take care of that.
        Look at this picture, study it a while, think about it. 

        It all comes out the same with or without the shims, it's just that the conventional way of adjusting them is much quicker and easier. The taper on the bearings assure everything will work as it should, shims or no shims, so long as the preload or float is adjusted properly. The key word being properly, not precisely, this isn't rocket science you have a little leeway.

        Knowing what you have just learned can save you a lot of time and toil the next time you get into your front wheel bearings. Install the spacers and shims if you simply must have it by "the book", but my book and thousands of others don't have them.

John Dandy
(theAutoist NOTE:  John Weimer's new "nom de plume")