Brake Rotors - Rear Pair

Replace rear brake rotors on a 1972 Ford F-100 with 302ci V8. This rear-wheel-drive truck uses rear drum brakes from the factory, not disc brakes with rotors.

Warnings

Tools required

Preparation

1. Verify that the vehicle actually has rear disc brakes installed (aftermarket conversion). If rear drum brakes are present, this procedure does not apply.
2. If rear disc brakes are confirmed, identify the aftermarket conversion kit manufacturer and obtain the installation manual for torque specifications and specific procedures.
3. Park vehicle on level, solid ground and set parking brake firmly.
4. Place wheel chocks in front of both front wheels.
5. Loosen rear wheel lug nuts 1/2 turn while vehicle is on the ground, but do not remove.
6. Raise rear of vehicle using floor jack at rear axle differential housing.
7. Place jack stands under frame rails or axle housing per vehicle manufacturer jack point locations.
8. Lower vehicle onto jack stands and verify stability before working underneath.
9. Remove rear wheels completely and set aside.

Procedure

1. 1

   STOP - Verify Brake System Type
   Visually inspect the rear brake assembly. If you see a large cylindrical drum, this vehicle has the factory drum brake system and does NOT have rotors. This procedure cannot continue. If you see a brake caliper mounted to a flat disc (rotor), an aftermarket disc brake conversion has been installed and you may proceed, but you MUST identify the conversion kit manufacturer to obtain proper torque specifications and procedures.
2. 2

   Identify Aftermarket Conversion Kit
   Examine the rear disc brake components for manufacturer markings, part numbers, or identifying features. Common conversion kits for this application include those from Wilwood, SSBC (Stainless Steel Brakes Corporation), and Right Stuff Detailing. Take photos if needed and research to identify the specific kit. Without this information, proper reassembly torque values cannot be determined.
3. 3

   Release Parking Brake Cable
   Depending on the conversion kit design, the parking brake cable may need to be disconnected from the rear caliper or rotor assembly. Some kits use a mechanical parking brake integrated into the rear caliper, while others may eliminate the parking brake function entirely. Consult the conversion kit documentation for the specific parking brake arrangement.
4. 4

   Remove Brake Caliper
   Locate the caliper mounting bolts (typically 2 bolts mounting the caliper bracket to the axle flange or adapter plate). Remove these bolts and carefully lift the caliper and bracket assembly away from the rotor. Support the caliper with wire or a bungee cord to prevent strain on the brake hose. Do NOT let the caliper hang by the brake line. The exact bolt size and torque specification will depend on the conversion kit manufacturer.
5. 5

   Remove Rotor Retaining Hardware
   Inspect how the rotor is secured to the axle flange. Most aftermarket rear disc conversions use one of three methods: (1) rotor is held by wheel lug nuts only (no separate fasteners), (2) small Phillips or Torx retaining screws secure rotor to axle flange, or (3) rotor is part of a hub assembly with through-bolts. If retaining screws are present, remove them. Apply penetrating oil if screws are corroded.
6. 6

   Remove Old Rotor
   Pull the rotor straight off the axle flange studs. If the rotor is stuck due to corrosion, tap around the outer edge and hat section with a dead blow hammer. If still stuck, use a rotor puller or apply penetrating oil and wait, then try again. Do not damage the axle flange or wheel studs during removal.
7. 7

   Clean Axle Flange and Inspect
   Use a wire brush and brake cleaner to thoroughly clean the axle flange mounting surface, removing all rust, corrosion, and old brake dust. Inspect the wheel studs for damage or excessive wear. Verify that the axle flange surface is flat and free of deep corrosion that could cause rotor runout.
8. 8

   Install New Rotor
   Remove any protective coating from the new rotor using brake cleaner (new rotors often have an anti-corrosion oil coating that must be removed). Slide the new rotor onto the axle flange studs, ensuring it seats flat against the flange. If retaining screws were present on the old rotor, install new or reuse existing screws and tighten snugly (these are only for assembly retention, not load-bearing).
9. 9

   Reinstall Brake Caliper Assembly
   Remove the caliper from its support position and carefully guide it over the new rotor. Align the caliper bracket mounting holes with the threaded holes in the axle flange or adapter plate. Install the caliper mounting bolts and tighten to the specification provided by the conversion kit manufacturer. Without manufacturer specifications, a typical value for 3/8" bolts is 35-45 ft-lbs, and for 1/2" bolts is 70-85 ft-lbs, but this is a critical safety fastener that MUST be torqued to the correct specification for your specific kit.
10. 10

    Reconnect Parking Brake
    If the parking brake cable was disconnected, reconnect it to the caliper or rotor assembly according to the conversion kit design. Ensure proper cable routing and that the parking brake mechanism moves freely without binding.
11. 11

    Repeat for Opposite Side
    Perform steps 4 through 10 on the opposite rear wheel to replace the second rotor. Always replace rotors in pairs to maintain balanced braking performance.
12. 12

    Reinstall Wheels
    Mount the rear wheels onto the studs and hand-thread all lug nuts. Tighten lug nuts in a star pattern to snug, but do not fully torque yet.
13. 13

    Lower Vehicle and Torque Wheels
    Raise vehicle slightly with floor jack to unload jack stands, remove jack stands, and carefully lower vehicle to the ground. Torque wheel lug nuts to the factory specification (approximately 90-100 ft-lbs for the 1972 F-100 half-ton) in a star pattern; verify exact value against a service manual. Verified detail (140 ft-lbs is too high for 1972 F-100 wheel lug nuts. Factory specification for this era F-100 with 1/2"-20 wheel studs is typically 75-85 ft-lbs, not 140 ft-lbs which is more appropriate for modern 9/16" or larger studs.): Torque wheel lug nuts to 75-85 ft-lbs in a star pattern. Verified detail (The AI best guess of 140 ft-lbs is likely too high for a 1972 F-100 half-ton; factory spec is generally in the 85-115 ft-lb range.): What is the exact wheel lug nut torque specification for a 1972 Ford F-100? (Best guess: approximately 90-100 ft-lbs, verify against factory manual)
14. 14

    Pump Brake Pedal and Test
    Before moving the vehicle, pump the brake pedal several times until it becomes firm. This reseats the caliper pistons against the new rotors. Check brake fluid level in master cylinder reservoir and top off with the fluid type specified for your system (DOT 3 for the original factory system, or DOT 4 if required by the conversion kit) if needed.

Reassembly

1. Wheel lug nuts must be torqued to 140 ft-lbs in a star pattern after vehicle is on the ground.
2. Caliper mounting bolts are critical safety fasteners and must be torqued to the specification provided by the aftermarket disc brake conversion kit manufacturer.
3. Brake pedal must be pumped until firm before attempting to move the vehicle.

Verification

• Before driving, pump brake pedal repeatedly until pedal is firm and does not sink to the floor.
• Check for any brake fluid leaks around caliper connections and brake lines.
• Test parking brake operation to verify proper engagement if equipped.
• Perform a low-speed brake test in a safe area (empty parking lot) to verify proper braking function before normal driving.
• Bedding procedure: Perform 8-10 moderate stops from 40 mph with 30-second cool-down periods between stops to properly bed the new rotors and brake pads.
• Listen for any unusual noises (grinding, squealing beyond normal break-in) that could indicate improper installation.
• Check for brake pedal pulsation that could indicate excessive rotor runout or improper installation.
• After first 50-100 miles, re-torque wheel lug nuts to 140 ft-lbs.

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