Brake Caliper Rebuild - Rear

Complete rebuild of rear brake calipers including disassembly, inspection, seal replacement, piston cleaning, and reassembly to restore proper braking function.

Warnings

Tools required

Parts

• Rear brake caliper rebuild kit (both sides) × 2 — Use OEM specification
• Brake caliper guide pin boots × 4 — Use OEM specification
• Brake caliper guide pin grease × 1 — High-temp synthetic brake grease
• Brake bleeder screw caps × 2 — Use OEM specification

Fluids

• DOT 4 Brake Fluid — 1 qt

Preparation

1. Park vehicle on level ground and engage parking brake
2. Place wheel chocks in front of front wheels
3. Disable high-voltage system following manufacturer lockout/tagout procedure and confirm with multimeter
4. Using floor jack, raise rear of vehicle and support on jack stands at designated frame lift points
5. Remove both rear wheels and set aside
6. Open brake fluid reservoir and use turkey baster to remove approximately half the fluid to prevent overflow during piston compression
7. Inspect brake system for existing leaks, damaged lines, or contamination before proceeding

Procedure

1. 1

   Remove brake caliper from mounting bracket
   Clean area around caliper with brake cleaner. Remove caliper guide pin bolts (typically 13-17mm) and carefully swing caliper upward. Support caliper with mechanics wire or bungee cord - do NOT allow caliper to hang by brake hose. Mark orientation of caliper for reassembly.
2. 2

   Disconnect brake hose from caliper
   Place drain pan under caliper. Using appropriate wrench (typically 11mm), disconnect brake hose banjo bolt from caliper while holding caliper body. Remove and discard copper crush washers. Immediately cap or plug brake hose to minimize fluid loss and contamination. Allow caliper to drain completely into pan.
3. 3

   Disassemble caliper housing
   Move to clean workspace. Remove caliper bleeder screw and cap. Remove any anti-rattle clips or pad retaining hardware. If caliper has dust boot retention ring, carefully pry it out with pick tool. Document orientation of all components with photos for reference during reassembly.
4. 4

   Remove caliper piston
   Place wooden block inside caliper to catch piston. Using compressed air at maximum 30 PSI, blow short controlled bursts into brake fluid inlet port to push piston out. Keep fingers clear of piston path. If piston is stuck, apply penetrating oil around dust boot and wait 15 minutes before repeating. Once piston moves freely, remove completely by hand.
   ⚠️Piston can eject with significant force causing injury. Always use wooden block to catch piston and keep hands clear of ejection path.
5. 5

   Remove and inspect seals
   Using plastic pick tool, carefully remove dust boot from caliper bore groove. Remove piston seal from inner groove, taking care not to scratch bore surface. Inspect caliper bore for scoring, pitting, corrosion, or uneven wear. Minor surface imperfections can be polished with very fine crocus cloth; deep scoring requires caliper replacement.
6. 6

   Inspect piston condition
   Clean piston thoroughly with brake cleaner and inspect chrome plating for scoring, pitting, peeling, or corrosion. Measure piston diameter with micrometer at multiple points and compare to caliper bore measurements - clearance should be 0.002-0.006 inches. Any defects in chrome plating require piston replacement. Check piston for straightness by rolling on flat surface.
7. 7

   Clean all caliper components
   Thoroughly clean caliper bore, piston, caliper body, and all passages with brake cleaner. Use brass wire brush on metal surfaces only - never use steel brush. Clean all fluid passages and bleeder screw hole. Dry completely with compressed air. Inspect caliper casting for cracks, especially around mounting ears and fluid passages. Any cracks require caliper replacement.
8. 8

   Prepare components for reassembly
   Lay out all new seals and components from rebuild kit. Verify kit completeness against manufacturer instructions. Pour small amount of fresh DOT 4 brake fluid into clean container for lubricating seals during installation. Ensure work area is completely clean and free of dirt, debris, or contaminants.
9. 9

   Install new piston seal
   Lubricate new piston seal with fresh brake fluid. Carefully install seal into inner groove of caliper bore, ensuring seal is not twisted and seats completely around entire circumference. Verify seal is fully seated in groove by running finger around perimeter - seal should be flush with groove bottom.
10. 10

    Install piston and dust boot
    Lubricate piston and caliper bore generously with fresh brake fluid. Lubricate new dust boot with brake fluid and install onto piston in correct orientation per rebuild kit instructions. Carefully insert piston into bore at slight angle, ensuring piston seal does not roll out of groove. Once piston is started, push straight into bore until it bottoms. Seat dust boot outer lip into caliper groove, ensuring boot is not twisted or pinched.
11. 11

    Service caliper guide pins
    Remove guide pins from caliper mounting bracket. Clean guide pins and bores thoroughly with brake cleaner. Inspect guide pins for wear, corrosion, or binding - replace if damaged. Install new guide pin boots from rebuild kit. Apply thin coat of high-temperature brake grease to guide pins and reinstall into mounting bracket, verifying smooth movement throughout travel.
12. 12

    Reinstall caliper to vehicle
    Install new copper crush washers onto brake hose banjo bolt. Position caliper onto mounting bracket in correct orientation. Thread banjo bolt through brake hose and into caliper body, tightening to secure caliper without overtightening (typically 18-22 ft-lbs - consult service data). Install and tighten caliper guide pin bolts. Install new bleeder screw cap.
13. 13

    Bleed brake caliper
    Fill brake fluid reservoir to MAX line with fresh DOT 4 fluid. Attach clear tubing to bleeder screw and submerge other end in container partially filled with brake fluid. Have assistant pump brake pedal 5 times and hold pressure. Open bleeder screw 1/2 turn until fluid flows, then close before pedal reaches floor. Repeat until fluid runs clear with no air bubbles. Never allow brake pedal to reach floor during bleeding.
    ⚠Monitor brake fluid reservoir constantly during bleeding. Never allow reservoir to run dry or air will enter ABS system requiring professional scan tool bleeding.
14. 14

    Complete second caliper
    Repeat steps 1 through 13 for opposite rear caliper. Maintain cleanliness and follow same inspection criteria for both sides. After bleeding second caliper, perform final system bleed starting with wheel farthest from master cylinder (typically right rear, left rear, right front, left front).
15. 15

    Final brake system check
    Fill brake fluid reservoir to MAX line. With vehicle still raised, pump brake pedal repeatedly until firm pedal is achieved - should require 3-5 pumps maximum. Check all caliper connections, bleeder screws, and brake hoses for leaks. Verify caliper pistons do not leak around dust boots. Install rear wheels and torque lug nuts to specification. Lower vehicle to ground.

Reassembly

1. Install rear wheels and torque lug nuts to manufacturer specification (typically 120-140 ft-lbs for EDV 500 - verify with service data)
2. Lower vehicle to ground and remove jack stands
3. Top off brake fluid reservoir to MAX line with fresh DOT 4 brake fluid
4. Re-enable high-voltage system following manufacturer procedures
5. Pump brake pedal firmly 10-15 times with vehicle stationary to fully seat pads against rotors

Verification

• With engine/drive system off, pump brake pedal - should achieve firm pedal within 3-5 pumps and maintain firmness without fading
• Start vehicle and verify brake warning lights extinguish after initial system check
• Perform careful low-speed test drive in safe area, testing brakes at increasing speeds from 5 mph to 25 mph
• Verify smooth, even braking with no pulling to either side and no unusual noises
• Check for proper regenerative braking integration - braking should feel smooth and consistent
• After test drive, re-inspect all caliper connections, bleeder screws, and brake lines for any signs of leakage
• Verify brake fluid level is still at MAX line - any significant drop indicates leak that must be corrected immediately
• Perform 10-15 moderate stops from 30-40 mph to properly bed new seals and verify consistent brake feel
• CRITICAL: If brake pedal feels soft, spongy, or travels more than halfway to floor, DO NOT drive vehicle - repeat bleeding procedure or seek professional service

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