Brake Caliper Rebuild - Rear

Complete disassembly, cleaning, inspection, and rebuild of rear brake calipers including replacement of seals, boots, and pistons if necessary, followed by bleeding and testing.

Warnings

Tools required

Parts

• Rear brake caliper rebuild kit (per caliper) × 2 — Use OEM Ford specification for 2021-2024 F-150
• Brake fluid × 1 — Motorcraft DOT 4 LV
• Brake caliper pistons (if damaged) — Inspect before ordering

Fluids

• Motorcraft DOT 4 LV Brake Fluid — 1 qt

Preparation

1. Park vehicle on level surface and set parking brake firmly
2. Loosen rear wheel lug nuts while vehicle is on ground
3. Raise rear of vehicle with floor jack and support securely on jack stands at manufacturer-specified lift points
4. Remove rear wheels completely
5. Verify you have complete rebuild kits for both rear calipers before beginning disassembly
6. Place brake fluid catch container under work area
7. Have clean workspace prepared for caliper disassembly with lint-free towels

Procedure

1. 1

   Remove brake caliper assembly
   Using a line wrench, carefully loosen the brake line fitting at the caliper. Allow brake fluid to drain into catch container. Remove caliper slide pin bolts and lift caliper off the rotor. Support caliper and completely disconnect brake line. Cap the brake line immediately to prevent contamination.
   ⚠Do not allow caliper to hang by the brake hose. Support it properly to avoid hose damage.
   Torque spec

   Line Fittings23 Nm (17 lb-ft)

   Caliper Slide Pin Bolts35 Nm (26 lb-ft)
2. 2

   Remove brake pads and caliper bracket
   Remove brake pads from the caliper bracket. Using appropriate socket, remove the two caliper bracket bolts securing the bracket to the knuckle. Remove bracket and set aside. Inspect rotor for wear or damage.
   Torque spec

   Bracket Bolts117 Nm (86 lb-ft)
3. 3

   Disassemble caliper
   Move to clean workbench. Remove dust boot from caliper piston using pick tool, being careful not to scratch caliper bore. Remove bleeder screw cap and inspect bleeder screw condition.
   ⚠Do not use sharp tools inside the caliper bore. Any scratches or gouges will cause seal failure and fluid leaks.
   Torque spec

   Bleeder Screw10 Nm (7 lb-ft)
4. 4

   Remove caliper piston
   Place a block of wood or several shop towels inside the caliper to catch the piston. Using compressed air applied to the brake line inlet port, carefully blow the piston out of the caliper bore. Use low pressure initially and increase gradually. Keep fingers clear of piston path.
   ⚠️Piston will eject with force. Keep hands and face clear. Use only enough air pressure to remove piston. Excessive pressure can cause injury.
5. 5

   Remove piston seal
   Using a plastic or wooden pick tool, carefully remove the piston seal from the groove inside the caliper bore. Inspect the bore carefully for any corrosion, pitting, or scoring. If bore is damaged beyond light surface corrosion, caliper must be replaced, not rebuilt.
   ℹ️Do not use metal tools to remove seals as they will damage the precision bore surface.
6. 6

   Clean and inspect caliper components
   Thoroughly clean caliper bore, piston, and all caliper surfaces with brake cleaner and lint-free towels. Inspect piston for chrome plating damage, pitting, or corrosion. Measure piston diameter with micrometer and compare to service specifications. Any damage to piston chrome plating requires piston replacement. Clean caliper bracket thoroughly and inspect slide pin bores.
   ⚠Even minor pitting or chrome damage on piston will cause seal failure. Replace piston if any damage is found.
7. 7

   Lubricate and install new piston seal
   Coat new piston seal from rebuild kit lightly with clean DOT 4 LV brake fluid. Carefully install seal into the groove in the caliper bore, ensuring it is seated completely and evenly around the entire circumference. Verify seal is not twisted or pinched.
   ⚠Use only DOT 4 LV brake fluid or silicone brake grease to lubricate seals. Never use petroleum-based products which will destroy rubber components.
8. 8

   Install piston and dust boot
   Coat piston generously with clean DOT 4 LV brake fluid. Carefully align piston with caliper bore and push in by hand, ensuring piston enters bore squarely. Push piston fully into bore. Install new dust boot from rebuild kit into the piston groove, then seat boot outer edge into caliper body groove. Verify boot is properly seated all around.
   ⚠Piston must enter bore straight and evenly. Cocking the piston will damage the seal and bore.
9. 9

   Service caliper bracket and hardware
   Clean caliper bracket slide pin bores thoroughly with wire brush and brake cleaner. Apply thin coat of silicone brake grease to slide pins. Install new slide pin boots from rebuild kit if included. Verify all anti-rattle clips and hardware are present and in good condition.
   Torque spec

   Caliper Slide Pin Bolts35 Nm (26 lb-ft)
10. 10

    Reinstall caliper bracket
    Position caliper bracket onto the rear knuckle. Install bracket bolts and torque to specification. Ensure bracket is seated flush against knuckle before final torquing.
    Torque spec

    Bracket Bolts117 Nm (86 lb-ft)
11. 11

    Install brake pads and caliper
    Install brake pads into caliper bracket with anti-rattle hardware. Connect brake line to caliper port using new copper washers if provided in rebuild kit. Thread fitting by hand first, then tighten to specification with line wrench. Position caliper over brake pads, align with slide pin holes, and install slide pin bolts with silicone brake grease applied to threads and contact surfaces. Torque to specification.
    Torque spec

    Line Fittings23 Nm (17 lb-ft)

    Caliper Slide Pin Bolts35 Nm (26 lb-ft)
12. 12

    Install bleeder screw
    Install bleeder screw with light coat of silicone brake grease on threads. Torque bleeder screw to specification. Install bleeder screw cap.
    ⚠Bleeder screws are brass and will strip or break easily if overtorqued. Use exact specification.
    Torque spec

    Bleeder Screw10 Nm (7 lb-ft)
13. 13

    Repeat for opposite side
    Repeat all disassembly, inspection, cleaning, and rebuild steps for the opposite rear caliper. Both rear calipers must be rebuilt for balanced braking performance.
14. 14

    Bleed brake system
    Fill master cylinder reservoir with fresh Motorcraft DOT 4 LV brake fluid. Starting with the caliper furthest from master cylinder (typically right rear), attach bleeder hose to bleeder screw with other end submerged in brake fluid in clear container. Have assistant pump brake pedal several times and hold pressure. Open bleeder screw 1/2 turn and observe fluid flow. Close bleeder screw before pedal reaches floor. Repeat until fluid flows clear with no air bubbles. Repeat process for left rear caliper. Check master cylinder level frequently and maintain proper level throughout bleeding process.
    ⚠️Never let master cylinder run dry during bleeding or air will enter ABS system requiring professional scan tool bleeding.
    ⚠Do not reuse brake fluid captured during bleeding. Always use fresh fluid from sealed container.
15. 15

    Install wheels and perform final torque
    Reinstall rear wheels onto hubs. Thread lug nuts by hand to prevent cross-threading. Lower vehicle until wheels just contact ground to prevent rotation. Torque lug nuts to specification in star pattern. Lower vehicle completely and remove jack stands.
    Torque spec

    Wheel Lug Nuts140 Nm (103 lb-ft)

Reassembly

1. Verify all brake line fittings are tight and leak-free
2. Confirm caliper slide pins move freely and are properly greased
3. Check brake fluid level in master cylinder reservoir and top off to MAX line with DOT 4 LV fluid
4. Pump brake pedal multiple times until firm pedal is achieved before attempting to move vehicle

Verification

• Start engine and pump brake pedal - pedal should be firm and hold pressure without sinking
• Check all brake line connections for leaks while assistant applies firm pedal pressure
• Test brakes at low speed in safe area - pedal should be firm with no sponginess, vehicle should brake straight without pulling
• Verify no brake fluid leaks around calipers after test drive
• Check master cylinder fluid level after test drive and top off if needed
• Perform 5-10 moderate stops from 30 mph to bed in new seals and verify proper operation
• If pedal feels soft or spongy, system requires additional bleeding - DO NOT DRIVE until proper pedal feel is achieved
• Monitor brake performance closely for first 100 miles and inspect for leaks

More procedures for this vehicle