DIY 14-Bolt Axle Disc Brake Conversion Kit

Are you ready to begin your disc brake conversion? We put together this handy guide to help you out. While this guide focuses on the 14 bolt full float, it can also be used with most other full float axles. The only major difference is that Jeep and Chevy Dana 60 rear axles have 7 mounting bolts instead of 4.

Before delving into this step-by-step guide, those working with a 14 bolt axle will want to determine which 14 bolt axle you have. Let’s start here:

How To Determine Which 14 Bolt Axle You Have

We created a guide to help you identify which GM 14 bolt axle you have. It will walk you through the basic steps for determining your axle type. Once you identify your axle, you’re ready to start the conversion. Here’s a video to supplement this guide.

Removing The Old Drums

• Get your vehicle up in the air, remove the tire and wheel, and then remove the axle shaft. First, remove the eight bolts that connect the axle shaft flange to the hub. Then you will be able to slide the shaft out. PRO TIP: Position a pan underneath because once you slide the shaft out, oil is going to come from the galley and leak out.
• Remove the bearings from the spindle. Most have a spring clip with a retainer known as a “keyway.” The best way to remove the keyway is with a pick and a magnet. Some newer axles require a special tool to remove this as one piece with the bearing.
• Remove the spindle nuts. The easiest way to do this is with a spindle nut socket. If you don’t have access to this spindle nut socket, a regular punch can be used. Just punch it around the outside and spin it off. (To properly torque the spindle nut when you reinstall it, you will still need a spindle nut socket.)
• Remove the old drum. Take the rubber plug out of the back of the backing plate and loosen the adjuster to allow the drum to come off. In extreme cases, the adjusters are rusted in place. If this happens, take a cutting torch and cut the backing plate around the four bolts on the outside of the axle housing and remove the entire drum brake assembly.
• With the drum pulled off of the backing plate, you’ll see four bolts that go into the axle housing. Remove those four bolts and then remove the entire drum brake assembly.
• Knock the lug studs out of the drum in order to remove the hub. We recommend taking a brass hammer and resting it on a stud, and then hitting it with another hammer. This will give you the focused force to knock the lug studs out. Repeat this with all the lug studs. (Be sure to clean up the hubs with a grinder and wire brush if they’re rusty. You may also want to paint them.)
  • Position the hub upside-down with the seal facing upwards.
  • Place the new rotor on top of the hub.
  • Line up all the holes and set the lug studs in all the holes.
  • Tap them in lightly and ensure that everything is centered.
  • Then use a bit more force and a cross-pattern to ensure that the rotor seats perfectly down on the hub.

7. Your brake conversion kit is ready to be installed.

How To Install Your Lugnut4x4 Conversion Kit

1. Start by installing the backing plate/caliper bracket to the flange on the axle where the backing plate was. Most people position the bracket to the rear. The bracket is designed to allow for mounting in a variety of positions. So, be sure that when you’re putting the bracket on that the brake bleeder can be positioned at the top of the caliper. Otherwise, air can get trapped inside the caliper and you’ll never be able to fully bleed the brakes.
2. The next step is attaching the new rotor to the old hub, using the lug studs that you removed earlier. Use the new rotor as a guide. (Make sure you have done a thorough job removing any rust from the hub before you put the rotor on the hub. It’s important that the hub face is perfectly flat where it mates to the rotor.)
3. Replace the wheel seal. Use a pry bar under the edge of the seal and quickly push down while holding the hub still. One you have the old seal out place the new one in position and tap it in. PRO TIP: Use a block of wood to evenly distribute pressure on the seal so it doesn’t get dented or install crooked.
4. Put the new rotor/hub on, replace the washer, and then put the bearing spindle nut back on and tighten it down with the spindle nut socket. Remember; tighten this to 50lb/ft and then back it off about a ¼ of a turn and check for the proper bearing pre-load. Do this by spinning the rotor and making sure it spins freely yet has no play. If you are installing new bearings, it’s a good idea to pack the bearings.
5. The spindle nut has recesses in it that will accept the Woodruff key. Install this key back into the recess, and then put the keeper ring back in. The Woodruff key locks the spindle nut into place so the bearing pre-load cannot change.
6. Before installing your brake pads and caliper, be sure to wipe down the rotor with mineral spirits, brake cleaner, or alcohol to remove the excess rust preventative oil on the rotor.
7. Place the caliper with pads over the rotor. Then take a mounting pin and slide it through the backside of the disc brake bracket, through the caliper, and just snug it. Do the same with the second pin, then torque them both down.
8. Insert the axle shaft. If your axle was sealed with RTV (silicone) make sure to clean the hub and axle shaft and apply a thin layer of RTV before inserting the shaft. You may have to wiggle it up and down to get the splines to engage properly in the differential. Then reinstall and torque the axle shaft flange bolts.
9. The factory brake line to the original brakes is a hard steel line. You will need to cut the line using a brake line cutting tool or tubing cutter. Bolt the flexible hose supplied with the kit to the caliper. Place a copper washer between the hose and the caliper and another between the hose and the banjo bolt. Allow enough flexibility to remove the caliper for maintenance and mark the hard line where you want it to connect. Once the line is cut to the length you need, slide the brake nut onto the tubing. Then use a flaring tool to create a double flare. This flare will allow you to connect the rubber or stainless steel brake line that comes in the kit to your brake line.
10. Add brake fluid and bleed the brakes.
11. You’re done!! Enjoy your new disc brake conversion!