Racing Rearend Build - Building The Ultimate Rearend, Part 2

Once the hub nut is correct, this tap slides into the keyway cut into the axle tube to lock the hub nut in place.

Button head screws attach the locking tab to the hub nut. Once everything is in place, there’s no way the hub nut can back off and screw up the preload you’ve worked so hard to set.

This caliper mount installation kit from Joe’s may not look like much, but after using it (you can see we’ve already torn into it) we won’t go without it ever again, as you will see.

Once the hub nut is correct, this tap slides into the keyway cut into the axle tube to lock the hub nut in place.

Bolt the caliper to the caliper mounting bracket, then slide the caliper over the rotor and bolt the bracket to the tube. Leave the bolts loose enough so that you can still slide things around a bit. Hargett prefers to mount the caliper brackets so that the calipers are vertical and directly behind the axle tubes to help protect them. These Wilwood units have bleeder valves at both ends of the caliper which is a great feature, but if yours don’t, make sure you have a bleeder valve at the top of the caliper.

Now it’s time to properly locate the brake caliper before drilling the bracket mounting holes into the axle tubes. The easiest way to do this is to thread a properly sized pipe nipple onto an air chuck, screw it into the fluid inlet on the caliper and use compressed air to extend the pads so that they’ve grabbed onto the rotor and locked everything in place. Notice the threaded hole just below the bolt on the caliper mounting bracket. That’s where we’ll drill the axle tube so we can permanently affix the bracket.

Here’s where the Joe’s mounting kit becomes so valuable. The axle tube must be drilled and tapped in line with the hole in the caliper mounting bracket. But that’s easier said than done. The mounting kit allows you to leave the caliper in place and ensures your hole is in the proper location and angle every time. The first step is to install the sleeve that guides the drill bit and holds it on the correct angle. It also protects the threads in the mounting bracket from damage from the spinning bit.

Now use the included bit to drill the two holes into the tube that the mounting bracket requires.

After the holes have been drilled, the mounting kit also includes the correct tap to cut the threads into the tubes. Now all that’s left is to clean the aluminum shavings out of the interior of the tube and bolt up the caliper mounting bracket permanently. Don’t forget to apply antisieze to all bolts that are threading into aluminum.

Although the 31-spline Bulldog axles are gun drilled, one end on each has a slug pressed into place. These allow you to install bolts on each end to use as spacers. Notice the nut that is also threaded onto the bolt before installing it onto the axle. This will be used as a lock-nut to keep things from moving once we’ve got the proper spacing for the axles. We haven’t done it here yet, but you may also want to grind the end of the head of the bolts smooth.

Slide both axles into the rearend. The ends of the bolts should contact each other in the center of the spool. The idea is to use the bolts as adjusters to hold the axles out just enough that the splines won’t grind on the end of the tubes.

Here’s a better view once the spacer bolts are properly adjusted. Because the bolts won’t allow the axles to slide into the spool any deeper, the outer splines are held away from the ends of the axle tubes and can’t grind into them.