Over pre-loading of the front wheel bearings after the wheel ends are reassembled is the most common cause of wheel bearing failure.

When installing the spindle nut pack, parts are assembled in the following order.
 
1st: Inner spindle nut with pin
2nd: Spindle washer
3rd: Outer spindle nut

First, install the inner spindle nut. It can be identified by the small pin protruding from the face of the nut. This pin faces outward, away from the bearing.

The pin protrudes from the nut approx. 1/16 to 1/8 inches. If the pin has been accidentally pushed back into the nut, you can push it back out from the backside of the nut with a small punch. It is imperative that the pin is in good shape, if in doubt, replace the nut.

Using a proper spindle nut socket, tighten the inner nut down nice and snug, then back the nut off approx an 1/8 to 1/4 of a turn. The wheel hub will rotate far too easy because there won’t be much pre-load on the wheel bearing. But that’s OK, move on to the next step.

Spindle nut set assembled in order

Next, inspect the spindle washer. There is a tab on the inside of the washer that fits into a key way machined into the spindle. This tab must not be rounded off or damaged in any way. If in doubt, replace it. The picture shows two washer styles. The washer on the left is for the Borg Warner automatice hub that was popular in the 1970’s and 80’s. The washer on the right is the standard type washer. 

Look closely at this picture of a spindle washer. Notice that the holes in the washer are not in line with the tab that fits into the key way of the spindle. Do not tighten or loosen the inner spindle nut to accommodate the spindle washer!

Slide the spindle washer onto the spindle. Does one of the holes in the washer drop perfectly over the pin of the inner spindle nut? If not, remove the washer, flip it over and reinstall it. The hole in the washer will then line up with the pin.

If you tighten down the washer and outer nut without the pin engaged into one of the holes in the washer, you will push the pin into the nut or crush it and the whole thing will come apart within a few hours of driving.

Once you are sure the spindle washer is properly placed, install the outer spindle nut and tighten it down.

Most “nuts and bolts” threads are not as perfectly cut as we might think. Thread a nut onto a bolt and you will see that the nut is a little loose on the threads of the bolt.

The same is true of the spindle and spindle nuts. That’s the  reason why we leave the inner nut a little loose by backing off the inner nut 1/4 of a turn. The inner nut will be forced to move on it’s threads when the outer nut is tightened down, restoring the necessary pre load on the bearings 

Inner spindle nut with pin

Auto hub and standard washers

Spindle washer closeup