Installation Notes

In order to provide proper clearance between the inboard face of the hub and the fasteners securing the brake backing plate, it is necessary to both remove the slinger flange from the backing plate and replace the four screws securing the plate to the axle housing. This is also a good time to have the axle housing geometry checked and straightened as needed. Many of the housings were manufactured to fairly broad tolerances and can have a set to them which can lead to premature axle failure.

Remove the four spot-welds securing the slinger flange to the backplate with a cold chisel or drill bit. Replace the four hex-head bolts attaching the backing plate to the axle housing with 5/16" x 1" button-head cap screws and securing with flat washers under nylon locking nuts. The screws are available from Mini Mania as Part No: BC0508, the nuts: NL1251.

Install the new hub and bearing assembly using new nuts. Keep in mind that they are threaded left and right-handed.

If you are using the old-style brakes, you will have to relocate the holes for the lower return springs. To accomplish this, install new shoes and determine a new location.

Bearing Replacement

When replacing a rear hub bearing, it is essential that the outer face of the new bearing protrudes from .001in to .004in beyond the outer face of the hub when the bearing is pressed into position. Minor variations in dimensions from manufacturer to manufacturer can result in the condition this bulletin addresses. This procedure ensures that the bearing is gripped between the locating shoulder in the hub and the driving flange of the axle shaft and that the seal is then properly compressed. Less protrusion permits play in the bearing and results in increasing the load on the axle . Excess clearance can also permit oil leaks.

The most convenient method of meeting thse conditions is to measure the thickness of the bearing and the depth of the bore in the hub before installing the bearing. Subtract the bore dimension from the bearing thickness. The difference should be .001 to .004 inches. If it is less than .001in., fabricate a shim of appropriate thickness using stock from a bearing house and install it on the shoulder in the hub under the bearing.

Should the thickness show a difference of greater than .004"., a thinner bearing should be used; or the hub machined to relieve it for proper fit; or the bearing should be ground thinner.

Should the hubs vary in bore depth from side to side, selective fitting of various bearings should result in the desired condition.