Brake Caliper Rebuild - Rear

Complete disassembly, cleaning, inspection, and rebuild of rear brake calipers on a 2023 Rivian EDV 500, including seal and piston replacement.

Warnings

Tools required

Parts

• Rear brake caliper rebuild kit (both sides) × 2 — Use OEM Rivian specification
• Brake caliper slide pin boots and hardware × 1 — Use OEM specification
• Copper crush washers for brake line (if applicable) × 4 — Use OEM specification
• Brake caliper assembly lubricant (silicone-based) × 1 — Use brake-specific silicone lubricant

Fluids

• DOT 4 Brake Fluid — 1 qt

Preparation

1. Park vehicle on level surface and place in Park mode
2. Enable Service Mode through vehicle interface to disable regenerative braking and ensure high-voltage system is safe
3. Disconnect 12V battery negative terminal and wait 5 minutes
4. Loosen rear wheel lug nuts while vehicle is on ground
5. Raise rear of vehicle using floor jack and support on jack stands at manufacturer-specified lift points
6. Place wheel chocks in front of front wheels
7. Remove rear wheels completely
8. Verify vehicle stability before working underneath
9. Clean brake caliper exterior with brake cleaner to remove road debris
10. Prepare clean workspace with plastic or wood surface protection for disassembled components
11. Open brake fluid reservoir and remove fluid to approximately 50% capacity to prevent overflow during caliper work
12. Label left and right calipers and keep hardware separate

Procedure

1. 1

   Remove rear brake caliper assembly
   Place drain pan under caliper. Remove caliper mounting bolts (typically two bolts securing caliper to bracket). Carefully lift caliper off rotor without letting it hang by brake hose. Support caliper with wire or bungee cord if needed temporarily. Mark brake pad positions and remove pads from caliper or bracket.
2. 2

   Disconnect brake hydraulic line
   Place absorbent material under brake line connection. Using appropriate wrench, disconnect brake line from caliper body by removing banjo bolt or unthreading brake line fitting. Immediately plug or cap both the brake line and caliper port to minimize fluid loss and prevent contamination. Collect any spilled brake fluid for proper disposal.
3. 3

   Disassemble caliper and remove pistons
   Take caliper to clean workspace. Remove caliper slide pins/guide pins if applicable. Using compressed air applied to the brake line port, carefully blow out the piston(s). Place wood block or thick cloth in front of piston to catch it - NEVER place fingers in front of piston during air removal as injury can occur. Apply air gradually; piston will pop out forcefully. For multi-piston calipers, block removed pistons and repeat for remaining pistons.
4. 4

   Remove seals and clean components
   Using plastic pick or wooden tool, carefully remove dust boot from caliper bore groove. Extract piston seal from inner groove in cylinder bore - do NOT use metal tools that could scratch bore. Remove all old seals, boots, and rubber components. Inspect hardware for corrosion. Discard all rubber components from rebuild kit.
5. 5

   Inspect caliper bore and pistons
   Thoroughly clean caliper bore and pistons with brake parts cleaner and lint-free towels. Inspect cylinder bore for scoring, pitting, corrosion, or wear. Minor surface rust can be addressed with brake hone; deep scoring requires caliper replacement. Measure piston diameter and bore diameter with micrometer - compare to manufacturer specifications. Check pistons for chrome flaking, scoring, or corrosion. Replace pistons if damaged. Inspect caliper body for cracks.
6. 6

   Hone caliper bore if necessary
   If cylinder bore has light surface rust or glazing, use brake hone with brake fluid as lubricant. Rotate hone at moderate speed while moving in and out of bore. Do NOT over-hone - only remove enough material to achieve smooth surface. Clean thoroughly with brake cleaner after honing. Dry completely with compressed air and lint-free towels. Re-inspect for smoothness.
7. 7

   Lubricate and install new piston seals
   Coat new piston seals from rebuild kit with clean DOT 4 brake fluid or supplied silicone brake lubricant. Carefully install square-cut seal into inner groove of caliper bore using fingers only - ensure seal seats completely and evenly in groove without twisting. Inspect seal position to confirm proper seating all around circumference.
8. 8

   Install dust boot and prepare piston
   Install dust boot into outer groove of caliper bore according to rebuild kit instructions (some install before piston, some after). Thoroughly coat new or inspected piston with clean brake fluid. Ensure piston surface is completely wet to prevent seal damage during installation.
9. 9

   Install piston into caliper
   Carefully align piston with caliper bore. Using gentle hand pressure or appropriate caliper tool, push piston squarely into bore. Ensure piston does not cock or bind - it should slide smoothly past seal. Push piston until it nearly reaches bottom of bore. If dust boot installs after piston, seat boot into piston groove now. Ensure dust boot is properly seated in both caliper and piston grooves. Repeat for all pistons in multi-piston calipers.
10. 10

    Reassemble caliper hardware
    Clean caliper bracket and slide pin bores thoroughly. Install new slide pin boots from kit. Lubricate slide pins with silicone brake lubricant (never petroleum-based grease). Install slide pins and ensure they move freely. Clean all mounting bolt threads and holes. Install any anti-rattle clips or hardware according to original configuration.
11. 11

    Reinstall caliper and connect brake line
    Position rebuilt caliper onto caliper bracket or mounting location. Install new copper crush washers on banjo bolt if applicable. Connect brake line to caliper and thread fitting or banjo bolt by hand first to avoid cross-threading. Tighten brake line connection - note that proper torque specification should be obtained from Rivian service documentation. Install caliper mounting bolts finger-tight initially.
12. 12

    Install brake pads and tighten mounting bolts
    Install brake pads in original orientation with anti-squeal shims if equipped. Ensure pads are properly seated in bracket or caliper. Tighten caliper mounting bolts - consult Rivian service documentation for proper torque specifications as none are available in current database. Verify caliper is secure and properly aligned with rotor.
13. 13

    Bleed rear brake caliper
    Attach bleeder hose to caliper bleeder screw with other end submerged in clean brake fluid in catch bottle. Have assistant pump brake pedal 3-4 times and hold pressure (or use pressure bleeder if available). Open bleeder screw 1/2 turn while pedal is depressed. Close bleeder before pedal reaches floor. Repeat until fluid flows without air bubbles. Top off brake fluid reservoir frequently during bleeding. Tighten bleeder screw when complete.
14. 14

    Complete second rear caliper
    Repeat entire procedure (steps 1-13) for opposite rear caliper. Work carefully and maintain same quality standards. Compare assembly to first completed caliper to ensure consistency.
15. 15

    Final brake system bleeding and testing
    Bleed all four wheels in proper sequence (typically RR, LR, RF, LF for this vehicle, but verify with Rivian documentation). Fill brake fluid reservoir to MAX line with fresh DOT 4 fluid. Reinstall rear wheels and tighten lug nuts to proper specification. Lower vehicle to ground and perform final lug nut torque. Reconnect 12V battery. Exit Service Mode. Pump brake pedal repeatedly until firm pedal is achieved before attempting to move vehicle.

Reassembly

1. Ensure all caliper mounting bolts and brake line fittings are properly torqued per Rivian specifications
2. Verify brake pads are correctly positioned and all anti-rattle hardware is installed
3. Confirm dust boots are properly seated in both caliper and piston grooves on all pistons
4. Check that brake fluid reservoir is filled to MAX line with fresh DOT 4 fluid
5. Verify no brake fluid leaks are present at any caliper or connection point
6. Ensure all bleed screws are tightened and dust caps reinstalled
7. Confirm wheels are torqued to specification and vehicle is safely lowered

Verification

• With engine off, pump brake pedal 10-15 times - pedal should become firm and maintain consistent height
• Start vehicle and verify brake pedal remains firm with no significant drop when pressure is applied
• Inspect all caliper connections and bleeder screws for any signs of brake fluid leakage
• Perform low-speed test drive in safe area - verify brakes engage smoothly without pulling to either side
• Test brakes at various speeds up to 25 mph - confirm straight-line stopping with firm pedal feel
• Check for unusual noises, vibrations, or uneven braking response
• Verify brake warning lights are not illuminated on dashboard
• After initial test drive, re-inspect all connections for leaks and re-check brake fluid level
• CRITICAL: Do NOT return vehicle to normal service until you have verified proper brake operation and firm pedal feel. If any concerns exist, seek professional brake system diagnosis immediately
• Recommend professional brake system inspection after 50-100 miles to verify proper operation and seal bedding

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