This procedure rebuilds the front brake calipers on a 2021-2024 Ford F-150 with the 3.5L EcoBoost V6, including disassembly, seal replacement, piston cleaning, reassembly, and bleeding.

Warnings

Tools required

Parts

• Front brake caliper rebuild kit (includes pistons, seals, boots, and hardware) × 2 — Use OEM Ford specification or quality aftermarket
• Brake bleeder screw dust caps × 2 — Often included in rebuild kit
• Copper crush washers for brake lines (if disconnecting) × 2 — Use OEM specification

Fluids

• Motorcraft DOT 4 LV Brake Fluid — 1 qt

Preparation

1. Park vehicle on level surface and set parking brake firmly
2. Loosen front wheel lug nuts while vehicle is on ground
3. Raise front of vehicle with floor jack and support securely on jack stands rated for vehicle weight. Never work under a vehicle supported only by a jack
4. Remove front wheels completely
5. Verify you have a complete caliper rebuild kit for both front calipers before beginning
6. Open brake fluid reservoir and check level. Remove fluid with turkey baster or syringe to bring level down to MIN line to prevent overflow during caliper service
7. Prepare clean workspace with lint-free rags and brake parts cleaner for caliper disassembly

Procedure

1. 1

   Remove brake caliper assembly
   Remove the two caliper slide pin bolts using a socket. Support the caliper with a wire or bungee cord to prevent strain on the brake hose. Do NOT let the caliper hang by the brake line. If rebuilding both sides, work on one caliper at a time to maintain a reference.
2. 2

   Disconnect brake line from caliper
   Place a drain pan under the caliper. Using a brake line wrench (flare nut wrench), carefully loosen and remove the brake line fitting from the caliper body. Be prepared for brake fluid to drain. Cap or plug the brake line immediately with a clean rubber cap to prevent fluid loss and contamination. Remove the copper crush washers and discard - new washers must be used during reassembly.
   ⚠Use only a proper line wrench (flare nut wrench) on brake line fittings. Standard open-end wrenches will round off the fitting.
   Torque spec

   Line Fittings23 Nm (17 lb-ft)
3. 3

   Remove caliper bracket if necessary
   If your rebuild requires bracket removal (for access or service), remove the two caliper bracket bolts using an 18mm socket. The bracket bolts are torqued to high specification. Set bracket aside. This step is optional depending on rebuild kit requirements but provides better access for thorough cleaning.
   Torque spec

   Bracket Bolts117 Nm (86 lb-ft)
4. 4

   Remove bleeder screw and dust cap
   Remove the bleeder screw dust cap. Using a 10mm wrench, carefully remove the bleeder screw from the caliper body. Set aside if reusing or replace with new screw from rebuild kit. Inspect bleeder screw threads for damage.
   Torque spec

   Bleeder Screw10 Nm (7 lb-ft)
5. 5

   Remove caliper piston
   Place the caliper body on a clean workbench with the piston facing up, positioned over several clean rags to catch fluid. Apply low-pressure compressed air (30-40 psi maximum) to the brake line inlet port. The piston will slowly push out. Keep fingers and body clear of the piston path. If piston does not move, tap the caliper body gently while applying air. Once piston starts moving, air pressure can be reduced. Remove piston completely and set aside.
   ⚠️Never exceed 40 psi air pressure. Higher pressure can cause the piston to eject with extreme force causing serious injury. Keep all body parts clear of piston travel path.
6. 6

   Remove old seals and boots
   Using a plastic pick or seal removal tool (never metal tools that can scratch the bore), carefully pry out the dust boot from the caliper body. Next, remove the piston seal from its groove in the caliper bore. Inspect the seal groove carefully for any debris or corrosion. Discard all old seals and boots.
   ⚠Do not use metal tools inside the caliper bore. Any scratches or scoring will cause brake failure. The bore surface must remain perfectly smooth.
7. 7

   Clean and inspect caliper bore and piston
   Thoroughly clean the caliper bore with brake parts cleaner and lint-free rags. Clean the piston exterior completely, removing all old brake fluid residue and contamination. Inspect the caliper bore for any scoring, pitting, rust, or corrosion. The bore must be mirror-smooth. If any damage is visible, the caliper cannot be rebuilt and must be replaced. Inspect piston for chrome plating damage, pitting, or scoring. Replace piston if any damage is present (included in most rebuild kits).
   ⚠Caliper bore damage cannot be repaired. Any visible scoring, pitting, or corrosion requires complete caliper replacement. Attempting to rebuild a damaged caliper will result in brake failure.
8. 8

   Install new piston seal
   Lubricate the new piston seal lightly with clean DOT 4 LV brake fluid from a sealed bottle. Carefully install the seal into the groove in the caliper bore, ensuring it seats completely and evenly around the entire circumference. The seal must not be twisted or pinched. Work the seal gently with clean fingers to ensure proper seating.
   ⚠Use only clean brake fluid to lubricate seals. Never use petroleum-based products, which will destroy rubber seals and cause brake failure.
9. 9

   Install piston and dust boot
   Lubricate the piston exterior and caliper bore lightly with clean DOT 4 LV brake fluid. Install the new dust boot onto the piston according to the rebuild kit instructions (some install on piston first, others install in caliper groove first). Carefully insert the piston into the caliper bore, ensuring it does not cock or bind. Push the piston squarely into the bore using hand pressure or a caliper piston tool. Seat the dust boot properly in both the caliper body groove and piston groove, ensuring no folds or pinches. The boot must seal completely around its entire circumference.
   ⚠Piston must enter bore perfectly straight. Any cocking or binding can damage the seal or bore, causing brake failure.
10. 10

    Reinstall bleeder screw
    Thread the bleeder screw (new or cleaned original) into the caliper body by hand, ensuring threads engage properly. Torque the bleeder screw to specification using a torque wrench. Do not overtighten as this will strip the aluminum caliper body threads. Install new dust cap on bleeder screw.
    ⚠Bleeder screw threads into soft aluminum. Overtightening will strip threads and destroy the caliper body. Use exact torque specification.
    Torque spec

    Bleeder Screw10 Nm (7 lb-ft)
11. 11

    Reinstall caliper bracket if removed
    If the caliper bracket was removed, clean the bracket mounting surface on the steering knuckle with a wire brush. Apply medium-strength thread locker to the caliper bracket bolt threads. Install the bracket and thread both bolts by hand first. Torque the bracket bolts to specification in a cross pattern using a torque wrench.
    Torque spec

    Bracket Bolts117 Nm (86 lb-ft)
12. 12

    Reconnect brake line to caliper
    Install new copper crush washers on both sides of the brake line banjo fitting (or on the threaded fitting as applicable to your caliper design). Thread the brake line fitting into the caliper body by hand to ensure proper thread engagement. Using a brake line wrench and torque wrench, torque the fitting to specification. Do not overtighten.
    Torque spec

    Line Fittings23 Nm (17 lb-ft)
13. 13

    Reinstall caliper to bracket
    Clean the caliper slide pins thoroughly with brake parts cleaner. Apply a thin coat of high-temperature silicone brake grease to the slide pin shafts (do not use petroleum-based grease). Position the caliper over the brake pads and bracket. Thread both slide pin bolts by hand, ensuring proper thread engagement. Torque the slide pin bolts to specification using a torque wrench.
    ⚠Use only silicone brake grease on slide pins. Petroleum-based grease will destroy rubber boots and cause caliper seizure.
    Torque spec

    Caliper Slide Pin Bolts35 Nm (26 lb-ft)
14. 14

    Bleed brake caliper
    Fill the brake fluid reservoir to the MAX line with fresh Motorcraft DOT 4 LV brake fluid from a sealed container. Attach a clear tube to the bleeder screw and submerge the other end in a container of clean brake fluid. Have an assistant slowly depress the brake pedal while you open the bleeder screw 1/2 turn. Close the bleeder before the pedal reaches the floor. Repeat this process until no air bubbles appear in the discharge tube and only clean fluid flows. Tighten the bleeder screw to specification. Check reservoir level frequently during bleeding and maintain above MIN line.
    ⚠️Air in the brake system will cause brake failure. Continue bleeding until absolutely no air bubbles are present and pedal is firm.
    Torque spec

    Bleeder Screw10 Nm (7 lb-ft)
15. 15

    Repeat for opposite side caliper
    Perform steps 1 through 14 for the opposite front caliper. Complete one caliper entirely before starting the second. After both calipers are rebuilt and bled, bleed the brake system again starting from the caliper farthest from the master cylinder (typically right rear, then left rear, then right front, then left front) to ensure all air is purged from the system.

Reassembly

1. Fill brake fluid reservoir to MAX line with fresh Motorcraft DOT 4 LV brake fluid
2. Reinstall front wheels and hand-tighten lug nuts in a star pattern
3. Lower vehicle to ground and torque wheel lug nuts to specification in star pattern using torque wrench
4. Pump brake pedal slowly until firm resistance is felt - pedal must be firm before moving vehicle
5. Check brake fluid reservoir level and top off to MAX line if needed
6. Inspect all brake line connections for any signs of leakage
7. Clean any spilled brake fluid from painted surfaces immediately with water

Verification

• With engine off, pump brake pedal multiple times. Pedal must become firm and hold position. If pedal is soft or spongy, air remains in system - rebleed completely
• Start engine and verify brake warning light is off on instrument cluster
• With vehicle stationary and engine running, apply firm brake pedal pressure. Pedal must remain firm and not slowly sink. Any sinking indicates internal leak or air in system
• Perform a low-speed test drive in a safe area. Test brakes at 5-10 mph initially. Braking must be smooth and even with no pulling to either side
• Inspect ground under vehicle after test drive for any signs of brake fluid leakage at caliper connections
• After test drive, recheck brake fluid reservoir level. Top off to MAX line if needed
• Recheck all torque specifications on wheel lug nuts, caliper bolts, and brake line fittings after first 50 miles
• During first 200 miles, avoid hard braking to allow new seals to properly seat

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