Brake Caliper Rebuild - Front

This procedure covers disassembly, inspection, seal replacement, and reassembly of the front brake calipers on a 2012-2018 Jeep Wrangler JK with 3.6L V6 engine.

Warnings

Tools required

Parts

• Front brake caliper rebuild kit (seals, dust boots, hardware) × 2 — Use OEM or quality aftermarket kit specific to front caliper
• Brake fluid × 1 — Mopar DOT 4
• Copper crush washers for brake line banjo bolts × 4 — Use OEM specification

Fluids

• Mopar DOT 4 Brake Fluid — 1 qt

Preparation

1. Park vehicle on level surface and engage parking brake
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 at frame rails
4. Remove both front wheels completely
5. Verify you have complete caliper rebuild kits for both sides before disassembly
6. Prepare clean workspace for caliper disassembly with parts washer or cleaning pan
7. Open brake fluid reservoir and remove fluid to approximately 1/2 full using turkey baster or fluid pump to prevent overflow during piston compression

Procedure

1. 1

   Remove brake caliper from bracket
   Using appropriate socket, remove the two caliper bolts that attach the caliper body to the caliper bracket. These are the slider pin bolts on the back side of the caliper. Support the caliper and carefully remove it from the rotor. Do NOT let it hang by the brake hose - support with wire or bungee cord attached to suspension component.
2. 2

   Disconnect brake line from caliper
   Place catch pan under caliper. Using a line wrench to prevent rounding, loosen and remove the brake line banjo bolt from the caliper body. Allow brake fluid to drain into catch pan. Remove and discard the two copper crush washers from both sides of the banjo fitting. Plug the brake line opening with a rubber cap or clean shop towel to prevent contamination.
   ⚠Brake fluid will drain from the line. Have catch pan positioned before loosening fitting.
3. 3

   Transfer caliper to clean workbench
   Move the caliper to your prepared clean workspace. Place several shop towels or rags around the caliper to catch brake fluid during piston removal. Inspect the exterior of the caliper for cracks, deep scoring, or damage. If caliper body is cracked or severely damaged, replacement rather than rebuild is required.
4. 4

   Remove caliper piston
   Remove the dust boot retaining clip if present. Using compressed air at low pressure (30 PSI maximum), carefully blow into the brake line inlet hole to push the piston out of the bore. Keep fingers clear of piston path. Apply air gradually until piston ejects. If piston is stuck, you may need to use a wooden dowel and gentle prying, but avoid damaging the piston or bore. Once piston is removed, inspect it for scoring, pitting, or chrome plating damage - replace caliper if piston is damaged.
   ⚠️Piston can eject with force. Keep hands and face clear. Use low air pressure only.
5. 5

   Remove old seals from caliper bore
   Using a plastic pick or wooden tool (never metal tools that can scratch the bore), carefully pry out the square-cut piston seal from the groove in the caliper bore. Remove the dust boot and any retaining hardware. Inspect the caliper bore carefully for scoring, pitting, or corrosion. Light surface rust can be cleaned, but deep pitting or scoring requires caliper replacement.
6. 6

   Clean caliper components thoroughly
   Using brake parts cleaner and clean lint-free towels, thoroughly clean the caliper bore, piston, and all internal passages. Use a soft wire brush on external areas only - never brush the bore surface. Clean the bleeder screw hole and threads. Dry all components with compressed air. The bore must be perfectly clean and free of any debris, old fluid residue, or contamination.
7. 7

   Inspect and prepare new seals
   Remove new seals from the rebuild kit and verify you have all components: piston seal, dust boot, boot retainer or clip, bleeder screw cap, and any slider pin boots/seals. Coat the new piston seal lightly with clean DOT 4 brake fluid. Do not use any petroleum-based lubricants which will damage rubber components.
   ⚠Only use DOT 4 brake fluid as lubricant. Petroleum products will destroy seals and cause brake failure.
8. 8

   Install new piston seal
   Carefully work the new piston seal into the groove in the caliper bore. Ensure the seal is seated completely around its entire circumference and is not twisted or pinched. The seal should sit flat in the groove with no protruding sections.
9. 9

   Install piston and dust boot
   Coat the piston with clean DOT 4 brake fluid. Install the dust boot onto the piston according to rebuild kit instructions (some boots install on piston first, others install in caliper bore first - follow kit instructions). Carefully insert the piston into the bore, ensuring it does not damage or dislodge the seal. Push piston squarely into bore - it should slide in smoothly with moderate hand pressure. Push piston fully into bore until dust boot seats properly. Install dust boot retaining clip if equipped.
10. 10

    Service caliper slider pins and hardware
    Remove slider pins from caliper bracket. Clean pins thoroughly with brake cleaner. Inspect pins for scoring or corrosion - replace if damaged. If rebuild kit includes new slider pin boots, remove old boots and install new ones onto bracket. Apply thin coat of high-temperature brake grease (included in most kits) to slider pins and reinstall into bracket boots.
11. 11

    Reinstall caliper to vehicle
    Position rebuilt caliper over rotor and align with caliper bracket. Install NEW copper crush washers on both sides of brake line banjo fitting. Connect brake line to caliper and install banjo bolt, torquing to specification using line wrench. Apply medium-strength thread locker to caliper slider bolt threads. Install caliper bolts and torque to specification.
    Torque spec

    Line Fittings23 Nm (17 lb-ft)

    Caliper Bolts102 Nm (75 lb-ft)
12. 12

    Repeat for opposite side
    Perform steps 1 through 11 for the opposite front caliper. Both front calipers should be rebuilt during this service to ensure even brake performance and avoid uneven brake wear.
13. 13

    Bleed brake system
    Fill brake fluid reservoir to MAX line with fresh Mopar DOT 4 brake fluid. Starting with the right front caliper, attach bleeder hose to bleeder screw and submerge other end in catch bottle with clean brake fluid. Have assistant pump brake pedal 3-4 times and hold pressure, then open bleeder screw 1/2 turn. Close bleeder screw before pedal reaches floor. Repeat until fluid flows clear with no air bubbles. Torque bleeder screw to specification. Repeat process on left front caliper. Check and refill reservoir frequently during bleeding process.
    ⚠Never allow brake fluid reservoir to run dry during bleeding or air will enter master cylinder.
    Torque spec

    Bleeder Screw16 Nm (12 lb-ft)
14. 14

    Final fluid check and pedal test
    Fill brake fluid reservoir to MAX line. Install reservoir cap. Pump brake pedal repeatedly until firm pedal is achieved. Pedal should feel firm and not sink slowly. If pedal is soft or sinks, additional bleeding is required. Check all brake line connections and caliper areas for fluid leaks while assistant applies firm brake pedal pressure.
15. 15

    Reinstall wheels and perform final checks
    Reinstall both front wheels. Thread lug nuts by hand first to prevent cross-threading. Torque lug nuts to specification in star pattern. Lower vehicle to ground and torque lug nuts again in star pattern to final specification. Pump brake pedal multiple times and verify firm pedal before test drive.
    Torque spec

    Wheel Lug Nuts156 Nm (115 lb-ft)

Reassembly

1. All torque specifications must be followed exactly as listed
2. Caliper bolts require medium-strength thread locker application
3. Brake line banjo bolts require NEW copper crush washers on both sides of fitting
4. Lug nuts must be torqued in star pattern in two stages: initial torque with wheels elevated, final torque with vehicle on ground
5. Brake system must be bled completely with no air bubbles visible in bleeder hose fluid flow

Verification

• Verify firm brake pedal with engine off - pedal should not sink slowly when held under pressure
• Start engine and verify brake pedal remains firm and does not sink
• Visually inspect all caliper mounting bolts, brake line connections, and bleeder screws for any brake fluid seepage
• Check brake fluid reservoir level - should be at MAX line
• Test drive vehicle in safe area at low speed (under 15 mph) and verify brakes apply evenly without pulling to either side
• Perform several moderate brake applications and verify firm, consistent pedal feel
• After test drive, recheck brake fluid level and inspect calipers for any signs of leakage
• Allow brakes to cool, then verify all caliper bolts and wheel lug nuts remain properly torqued
• Before returning to normal service, perform brake test from 30 mph in safe area to ensure full braking capability

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