SERVICING FRONT WHEEL BEARINGS ON WIRE WHEEL CARS

SERVICING FRONT WHEEL BEARINGS ON WIRE WHEEL CARS
by Mr. Finespanner®©

 

Years ago in Texas I opened up the front end on a BJ8 that had had the wheel bearings replaced only about 2,000 miles previously. The owner was complaining about noises and nasty vibrations. I checked and found the hub end float to be in excess of 3/16ths of an inch on both sides. Upon disassembly the bearings came out with a purple tinge to them and they rattled like castanets – completely hosed in 2,000 miles. In addition, the spacer, or distance piece as it’s known in English, was missing, along with any shims that surely once had been there. It turns out that the Healey "expert" who had done the first bearing replacement just decided that the distance pieces and shims were extra parts that the car did not actually require. "Other cars don’t have ‘em, that means Healeys don’t need ‘em, either." It’s hard to imagine BMC spending the money to put unnecessary parts on a car, though. I always tend to be somewhat skeptical when I hear someone redesigning auto components on their own, not so much because I’m an originality freak but because I know they are usually not qualified to make such a judgment in the first place. For that matter, front wheel bearing R&R is not a job to be undertaken by anyone not well experienced in things mechanical. Too much depends on getting it right.
 

If you research front wheel bearings in the factory manuals you will find that there is no axle nut torque specification for Hundreds, and that BN1’s and disc-wheeled cars use bearings with a spacer but no shims. These bearings need to be replaced "should a very positive movement be apparent" when the hub is pushed or pulled parallel to the stub axle. I expect opinion may differ as to what constitutes "very positive" end float, so I’m glad it’s not a topic here. With the later BN2’s the shim-and-distance-piece setup became SOP for wire wheel cars, with the initial torque spec being ‘tighten the stub axle nut until resistance is felt turning the hub, then back off to the nearest notch lining up with the hole for the cotter pin.’ This was changed to an exact specification of 40 – 70 lb./ft. of torque for the six cylinder cars, a range which allows the axle nut to be turned as far as it needs to go for at least one notch on the nut to line up for the cotter pin.
 

How can you tell if your front wheel bearings need work? To check them, jack up the front of the car, support well with jack stands, and remove the wheels. Slacken the brake adjusters or back off the pads as the case may be, so that the hub can spin freely with no interference from the brakes. Then spin the hub and check for free rotation, grinding noises, and vibration. Next, grasp the hub with one hand and with the other hand hold the base of the lower king pin collar part of the stub axle assembly just above the fulcrum pin, behind the backing plate. Try to move the hub in and out parallel to the stub axle. Grabbing the lower king pin collar will enable you to differentiate between flop from king pin wear and hub movement. If there is any detectable movement between the hub and the backing plate the bearings need attention.
 

The shop manuals give fairly explicit instructions for wheel bearing R&R, but it’s not a job for a beginner and some special tools are required, the most esoteric of which is the extractor for the dust covers. These little guys used to be a standard item in the tool kit, but were discontinued in later cars, possibly because too many people were getting into trouble trying to use them. At any rate, the extractor is pretty essential for clean removal of the dust cover and reproductions are available from major vendors. Various long punches will be needed to remove the outer races from the hubs along with a set of bearing race drivers to get the new races installed back in again. A supply of the appropriate shims is also vital, since the old ones may not be the proper sizes or in good enough condition to be reused. Healey wheel bearing shims are available in four thicknesses – .003", .005", .010", and .030". BJ8 shims are the same as MGB (BJ8 front wheel bearings are also the same as Volkswagen Transporter). The object is to combine the shims so that there is zero end float on the hub BUT ALSO NO DRAG ON THE BEARINGS when the axle nuts are torqued to 40 – 70 lb./ft. This can be a complicated process.

 

Over the years I’ve seen and tried several different techniques for fitting front wheel bearings and adjusting end float, and the method I like best is that of Peter Genovese of C.A.R.S. in Highland, NY, which I believe is the same as what is in the Bentley manual. It is certainly the cleanest and most straightforward, because you set up for zero play before greasing the bearings. Assemble the bearings, spacer, and shims according to the directions in the factory manual, using clean parts. Once you have configured the shims for zero end float and zero drag resistance at 40 – 70 lb./ft. of torque you then remove the nut and hub, pop out the bearings and grease ‘em up, and put it back together with the shim combination you have chosen. The nice thing about using clean, ungreased parts is that you don’t mistake seal drag or slowing from the viscosity of the grease for drag caused by tightening the axle nut. And anyone who has tried fingertip-grappling with greasy shims inside the confines of a hub splined extension will appreciate the advantages, too.
 

I do not recommend tightening the axle nut to seat the races as it says in the book. This can "brinell" the races and lead to quick failure of the new bearings. It’s better to use race drivers with a hammer or press, and of the two, I prefer a hammer. You can feel the change in vibration through the hammer handle when that last stroke drives the race home. Presses aren’t quite as sensitive, even arbor presses. If your bearings are in good condition they can be reused. Clean them thoroughly in some good solvent and examine the rollers and races for cracks, chips, scratches, and discoloration. Bearings are not too outrageously priced and easy enough to come by, so acquiring new ones is not that onerous. Front wheel bearings should be checked for wear every 5,000 miles and serviced (cleaned, replaced as necessary, greased, and repacked) every 25,000 miles.

 

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