Brake Caliper Rebuild - Rear

Complete disassembly, inspection, cleaning, and rebuild of rear brake calipers including seal replacement, piston cleaning, and system bleeding on the 2022 Rivian EDV 500.

Warnings

Tools required

Parts

• Rear brake caliper rebuild kit (includes pistons, seals, dust boots, hardware) × 2 — Use OEM Rivian specification
• Brake caliper bleeder screw caps × 2 — Use OEM specification
• Copper crush washers for brake line banjo bolts × 4 — Use OEM specification

Fluids

• DOT 4 Brake Fluid — 1 qt

Preparation

1. Park vehicle on level ground and ensure parking brake is released (if rear electronic parking brake, may need diagnostic tool to retract)
2. Power down the vehicle completely and wait 5 minutes for high-voltage systems to discharge
3. Disconnect 12V battery negative terminal and isolate cable
4. Loosen rear wheel lug nuts while vehicle is on ground
5. Raise rear of vehicle and support securely on jack stands at designated lift points per Rivian service manual
6. Remove rear wheels completely
7. Verify brake system is cool to touch before proceeding
8. Place catch pan under work area to collect brake fluid
9. Take photos of caliper orientation, brake line routing, and hardware positions for reference during reassembly
10. If vehicle has electronic parking brake actuators on rear calipers, verify you have the necessary scan tool or procedure to retract actuators

Procedure

1. 1

   Remove rear brake calipers
   Remove brake caliper mounting bolts (typically 2 bolts per caliper). Support caliper and carefully disconnect brake line banjo bolt, allowing fluid to drain into catch pan. Cap brake line immediately with rubber cap or tape to prevent contamination. Remove caliper from vehicle. Note: If electronic parking brake actuator is present, disconnect electrical connector before removing caliper.
   ⚠Do not let caliper hang by brake hose as this can damage internal hose structure and cause brake failure.
2. 2

   Initial disassembly and inspection
   Place caliper in clean work area. Remove dust boots from pistons carefully. Inspect caliper body for cracks, excessive corrosion, warping, or damage. If caliper body is damaged, replacement rather than rebuild is required. Remove any external hardware, anti-rattle clips, and pad retaining springs. Clean exterior of caliper with brake cleaner.
3. 3

   Remove caliper pistons
   Using compressed air method: Place a block of wood in front of pistons to prevent complete ejection. Apply low-pressure compressed air (30-40 PSI maximum) to brake fluid inlet port. Pistons will slowly emerge; control their movement with the wood block. Alternatively, if pistons are not severely seized, they may be removed with piston removal tool. Remove all pistons from caliper bore. NEVER place fingers directly in line with piston path during removal.
   ⚠️Pistons can eject with extreme force causing crush injuries. Always use wood block or protective barrier and never exceed 40 PSI air pressure.
4. 4

   Remove internal seals
   Using a wooden or plastic pick (never metal tools), carefully remove piston seals from their grooves in the caliper bore. Remove all old seals completely. Inspect seal grooves for scoring, pitting, or corrosion. Minor surface rust can be cleaned; deep scoring requires caliper replacement.
5. 5

   Clean and inspect caliper bores
   Thoroughly clean caliper bores using brake parts cleaner and lint-free towels. Use brass wire brush to remove any corrosion or buildup. If minor corrosion is present, very lightly hone bores with fine-grit caliper hone using brake fluid as lubricant (do not dry hone). Inspect bores for pitting, scoring, or damage. Surface must be smooth and free of defects. Dry completely with compressed air and lint-free towels.
6. 6

   Inspect and prepare pistons
   Clean old pistons thoroughly (or use new pistons from rebuild kit if included). Inspect piston surfaces for scoring, corrosion, or chrome plating damage. Any piston with damaged plating or deep scoring must be replaced. Clean pistons with brake cleaner and dry with lint-free towels. Ensure pistons are completely free of contamination.
7. 7

   Install new piston seals
   Lubricate new piston seals lightly with fresh DOT 4 brake fluid (never use petroleum-based lubricants). Carefully install seals into caliper bore grooves using fingers only. Ensure seals are seated evenly in grooves with no twists or folds. Verify seals sit below the bore surface and are not pinched or damaged.
8. 8

   Install pistons
   Lubricate piston outer surfaces and new dust boots with silicone brake assembly grease. Carefully insert pistons into caliper bores by hand, ensuring they enter straight without cocking to one side. Apply steady, even pressure. Pistons should slide in smoothly; excessive force indicates misalignment or contamination. Install new dust boots over pistons and seat into caliper body grooves.
9. 9

   Clean and prepare caliper mating surfaces
   Clean caliper mounting bracket and all mating surfaces with brake cleaner. Remove any rust or corrosion from slide pin bores. If caliper uses slide pins, inspect pins for corrosion or wear and replace if necessary. Lubricate slide pins with silicone brake grease (high-temperature brake-specific grease only). Clean brake line banjo bolt and replace copper crush washers with new ones.
10. 10

    Reinstall calipers to vehicle
    Position rebuilt caliper onto mounting bracket. Install NEW copper crush washers on brake line banjo bolt (one on each side of fitting). Connect brake line to caliper and hand-tighten banjo bolt. Install caliper mounting bolts and tighten to manufacturer specification (torque values not provided in database; consult Rivian service manual for exact specifications). Once caliper is secure, torque brake line banjo bolt to specification. If electronic parking brake actuator is present, reconnect electrical connector.
11. 11

    Bleed rear brake system
    Fill brake fluid reservoir with fresh DOT 4 brake fluid. Bleed rear calipers using proper sequence (typically starting with wheel furthest from master cylinder). Attach bleeder hose to caliper bleeder screw, submerge other end in catch bottle with clean fluid. Open bleeder screw 1/4 to 1/2 turn. Have assistant slowly depress brake pedal (or use vacuum bleeder). Close bleeder screw before pedal reaches bottom. Repeat until fluid flows clear with no air bubbles. Maintain reservoir level throughout bleeding process. Tighten bleeder screws to specification and install new bleeder caps.
    ⚠️Never allow brake fluid reservoir to run dry during bleeding as this will introduce air into ABS module requiring specialized equipment to bleed.
12. 12

    Install brake pads and complete reassembly
    Install brake pads into caliper or mounting bracket per original configuration. Ensure anti-rattle clips and hardware are properly installed. Verify all components move freely without binding. Check that brake lines are not twisted or kinked. Install wheels and hand-tighten lug nuts.
13. 13

    Lower vehicle and perform initial checks
    Lower vehicle to ground. Torque wheel lug nuts to manufacturer specification (consult Rivian service manual for exact torque value). Reconnect 12V battery. Check brake fluid reservoir level and top off with DOT 4 fluid to MAX line. With vehicle still in park, pump brake pedal multiple times until firm pedal is achieved. Pedal should feel firm and not sink slowly to floor.

Reassembly

1. Reassembly is included in the main procedure steps above
2. Ensure all brake hardware including anti-rattle clips are reinstalled exactly as found during disassembly
3. Verify brake lines have no kinks, twists, or contact with suspension or wheel components throughout full suspension travel
4. Double-check all caliper mounting bolts and brake line connections are properly torqued

Verification

• With engine off, pump brake pedal 20-30 times. Pedal should become firm and not sink to floor when held under constant pressure for 30 seconds
• Check brake fluid reservoir level is at MAX line with no visible air bubbles in fluid
• Inspect all brake connections for leaks. Look for fluid seepage at caliper banjo bolts, bleeder screws, and piston dust boots
• Perform slow-speed test drive in safe area (empty parking lot). Verify brakes engage smoothly without pulling to one side
• Perform 20-30 gentle brake applications from 15-20 mph to properly seat brake pads and bed-in system
• After bed-in procedure, perform moderate brake test from 30 mph to verify stopping power is equal and vehicle tracks straight
• Recheck brake fluid level after test drive and top off if necessary
• Listen for any unusual noises during brake application (grinding, squealing may indicate hardware issues)
• If electronic parking brake is equipped, verify parking brake engages and releases properly using vehicle controls
• Before returning to normal driving, verify brake pedal feel is firm and consistent with normal operation. If pedal feels soft or spongy, repeat bleeding procedure

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