Installation Guide

 14 Bolt Disc Brake Conversion Installation

This procedure applies to most 1973–2000 Corporate 14-bolt full-floating rear axles found in:

Chevrolet C/K 2500 and 3500

GMC C/K 2500 and 3500

Suburban 2500

Many cab-and-chassis trucks 

To complete the installation you will need these parts from a 2000-2006 Chevrolet Silverado or GMC Sierra 2500 HD

• Backing plates (GM part # 88965717 left and right)

• Parking brake shoes and hardware (GM part # 25904969 shoes, 15817888 hardware)

• Brake rotors (GM part # 15712801 left, 15712803 right)

• Brake calipers (GM part # 19331021 left, 19331022 right) 

• Caliper brackets (GM part # 25997047 left, 25997048 right)

• Brake pad set (GM part # 19210705)

• Parking brake cables and mounting brackets

• Disc/ disc proportioning valve

• Flexible brake hoses to connect rear calipers

• Medium strength Threadlocker - Blue (Loctite or Permatex) 

Removal

Step 1 – Prepare the Vehicle

1. Park on a level surface.

2. Set the transmission in Park (or in gear for manual transmissions).

3. Chock the front wheels.

4. Loosen the rear wheel lug nuts slightly.

Step 2 – Raise the Rear

1. Release the parking brake

2. Lift the rear axle using a floor jack

3. Support both axle tubes securely with jack stands.

4. Remove the rear wheels

Step 3 – Remove the Axle Shafts

1. Place a drain pan under the hub.

2. Remove the eight axle flange bolts.

3. Tap the axle flange gently with a dead blow hammer to break the gasket seal.

4. Carefully slide the axle shaft straight out of the housing.

5. Set the axle aside on a clean surface.

Step 4 – Remove the Hub Locking Hardware

Depending on the year or your axle, you’ll have either a lock ring or a lock clip retaining your spindle nut. A spindle nut socket is helpful for this step, but a punch and hammer can also work. 

Lock Ring

1. Slightly bend locking tabs away from spindle lock nut

2. Remove spindle lock nut, lock washer, and spindle nut

Lock Clip

1. Remove outer locking clip or retainer

2. Remove square spindle nut key from the keyway

3. Remove outer spindle nut, inner lock washer (if equipped), and inner adjusting nut

Keep all parts in the order they were removed.

Step 5 – Remove the Hub and Drum Assembly

1. Support the hub with both hands.

2. Pull the hub and brake drum straight off the spindle. 

Note: The hub and drum together can weigh 60–80 pounds, so use caution. Depending on brake shoe adjustment, you may have to back the shoes off to be able to remove the drum. 

Step 6 – Separate the Drum from the Hub

The drum is retained by the wheel studs.

1. Lay the drum and hub assembly drum side down.

2. Drive the wheel studs out using a brass drift and hammer.

3. Lift the hub out of the drum and set aside.

Step 7 - Remove drum brake hardware and backing plate from axle housing

1. Remove all the drum brake hardware and shoes by removing the clips and springs

2. Disconnect and plug brake line from wheel cylinder. 

3. Remove the 4 backing plate bolts and remove the backing plate

All that should remain is the spindle and original backing plate mounting bracket. Continue to Install.

Install

Step 1 

Take a 1/2” drill bit and drill out the threads of the 4 holes in the backing plate bracket. This makes room to thread the new 1/2” bolts into the new bracket from the backside. 

Step 2

Due to the many small differences between 14 bolt housings, some axles might require some grinding to gain clearance for the adapter bolts to sit flat coming through the backside of the original backing plate bracket. There may also be a small amount of weld grinding necessary on the spindle side to be able to slide the bracket all the way on flush with the original backing plate bracket. Make sure both the new bracket and mounting hardware sit all the way flush against the original backing plate 

Step 3

Place adapter bracket all the way on against the original backing plate bracket, making sure to have the raised lip of the adapter facing out toward the spindle. Put lock washers on the supplied bolts in the kit and thread into adapter through the original backing plate bracket. Medium thread locker blue is recommended on these bolts as well. Make sure the bolts go as far through the adapter as possible without protruding through the other side, or else this will cause the new backing plate to mount incorrectly on the next step. Slight grinding or filing might be necessary to ensure the bolts are flush with the adapter. Torque to 90 ft lbs.

Step 4

Place supplied bushings into your 2000-2006 Chevrolet/ GMC 2500 HD backing plates (may require a couple taps with a hammer). Then bolt up the backing plate to the adapter using the flat washers and medium thread locker blue, making sure the bolts don’t protrude through the opposite side of the adapter. Torque to 90 ft lbs.

Step 5

Take your hubs that were removed from the brake drums earlier and replace it with your 2000-2006 Chevrolet/ GMC 2500 HD brake rotor. Flip them over and reinstall the wheel studs through the rotor taking care not to damage the stud threads. Make sure the wheel studs are long enough to extend through your wheels and lug nuts to achieve correct mounting. Mount hub to spindle and tighten wheel bearings to correct preload and lock down spindle nut per manufacturer specs. 

Step 6

Clean and reinstall axle shaft using either a new gasket or sealant. Torque axle flange bolts down to 115 ft lbs.

Step 7

Clean rotors with brake cleaner and install brake pads and brake calipers. 

Note : Flexible brake lines will be required to connect to your new disc brake calipers to allow for movement when the brakes operate and self adjust. A disc/disc proportioning valve is REQUIRED to make the brakes operate properly. The rear brakes will not work correctly if you have a disc/drum proportioning valve as it will make the rear brakes drag.

Step 8 

Connect brake lines and bleed system of all air. Route parking brake cables and connect to your existing parking brake cable connectors. Additional or modifited mounts may be required to adapt the 2000-2006 Chevrolet/ GMC 2500 HD parking brake cables to your vehicle. 

Step 9

Check for leaks and test rear brake operation.  Top off brake fluid level in master cylinder.

Step 10

Mount wheels and snug up the lug nuts. Lower vehicle down and torque wheels to specification. Top off rear differential fluid if needed. Proceed to test drive.

Enjoy the reliability and performance of modern rear disc brakes with a built in parking brake!