Parking Brake Actuator

This procedure replaces the electronic parking brake actuator motor on the rear caliper assembly of a 2014-2018 Chevrolet Silverado 1500 with 5.3L V8.

Warnings

Tools required

Parts

• Electronic parking brake actuator motor × 1 — ACDelco 84664602 or equivalent OEM
• Brake fluid (top-off) × 1 — ACDelco DOT 4

Fluids

• ACDelco DOT 4 Brake Fluid — 0.25 qt

Preparation

1. Park vehicle on level, solid surface and engage parking brake (if functional). Place transmission in Park.
2. Chock the front wheels securely on both sides.
3. Connect scan tool to OBD-II port and verify communication with electronic parking brake control module.
4. Using scan tool, enter EPB service mode and command the parking brake actuator to fully retract. Wait for confirmation that actuator is in service/retracted position.
5. Loosen rear wheel lug nuts while vehicle is on ground (do not remove).
6. Raise rear of vehicle and support securely on jack stands rated for vehicle weight. Position stands under frame rails, never under axle or suspension components.
7. Remove rear wheels completely and set aside.
8. Verify vehicle stability before working underneath.

Procedure

1. 1

   Disconnect parking brake actuator electrical connector
   Locate the electrical connector on the rear caliper assembly connected to the EPB actuator motor. Press the locking tab and disconnect the connector. Secure the connector away from the work area to prevent damage or contamination with brake fluid.
2. 2

   Remove caliper slide pin bolts
   Remove the upper and lower caliper slide pin bolts from the rear caliper. These bolts secure the caliper to the bracket. Once removed, carefully pivot the caliper upward off the rotor. Do NOT allow the caliper to hang by the brake hose.
   ⚠Never let the caliper hang by the flexible brake hose as this can cause internal hose damage and brake failure.
   Torque spec

   Caliper Slide Pin Bolts35 Nm (26 lb-ft)
3. 3

   Support and secure caliper
   Using a caliper hanger, heavy wire, or bungee cord, suspend the caliper from the suspension or frame. Ensure there is no tension on the brake hose and the caliper is securely supported. Remove the brake pads from the caliper bracket and set aside if reusing.
4. 4

   Remove parking brake actuator mounting fasteners
   Locate the two mounting bolts that secure the EPB actuator motor to the rear of the caliper body. These are typically 10mm hex bolts. Remove both mounting bolts and retain them if reusing. Note the orientation of the actuator before removal.
   ℹ️Some brake fluid may seep from the actuator mounting area. Have a catch pan positioned underneath.
   Torque spec

   Mounting Bolts34 Nm (25 lb-ft)
5. 5

   Remove parking brake actuator
   Carefully pull the parking brake actuator motor assembly straight away from the caliper body. The actuator shaft will disengage from the caliper piston mechanism. Inspect the O-ring seal on the actuator and the mating surface on the caliper for damage or debris. Clean the caliper mounting surface with brake cleaner if necessary.
6. 6

   Inspect caliper piston and mechanism
   With the actuator removed, visually inspect the caliper piston and internal parking brake mechanism for damage, excessive wear, or corrosion. Verify the piston is fully retracted as commanded by the scan tool. If any damage is found, caliper replacement may be necessary instead of just actuator replacement.
7. 7

   Prepare new actuator for installation
   Remove the new parking brake actuator from packaging. Verify it matches the original actuator. Check that the new actuator's O-ring seal is properly seated in its groove. Lightly lubricate the O-ring with clean brake fluid (not silicone grease). Verify the actuator shaft is in the retracted position to match the caliper piston.
   ⚠Do not use petroleum-based lubricants on brake system O-rings as they will cause seal failure. Use only brake fluid or approved rubber lubricant.
8. 8

   Install new parking brake actuator
   Align the new actuator motor with the mounting holes on the caliper body. Carefully engage the actuator shaft with the caliper piston mechanism while pushing the actuator onto the caliper. Ensure the O-ring is not pinched or damaged during installation. The actuator should seat flush against the caliper body.
9. 9

   Install actuator mounting bolts
   Insert both actuator mounting bolts and hand-thread them to avoid cross-threading. Tighten both mounting bolts to the specified torque in a cross-pattern to ensure even seating. Apply medium-strength threadlocker if specified by the actuator manufacturer (verify replacement part instructions).
   Torque spec

   Mounting Bolts34 Nm (25 lb-ft)
10. 10

    Reconnect actuator electrical connector
    Reconnect the electrical connector to the new parking brake actuator motor. Ensure the connector locks fully with an audible click. Verify the connector boot is properly seated to prevent water intrusion.
11. 11

    Reinstall brake pads and caliper
    If removed, reinstall the brake pads into the caliper bracket. Apply a thin coat of silicone brake grease to the caliper slide pins and pin bores. Position the caliper over the brake pads and rotor. Install the upper and lower caliper slide pin bolts, ensuring the slide pins move freely. Torque the slide pin bolts to specification in the order: lower bolt first, then upper bolt.
    ⚠Ensure brake pads are properly seated in the bracket and that the caliper slides freely on the pins before final tightening.
    Torque spec

    Caliper Slide Pin Bolts35 Nm (26 lb-ft)
12. 12

    Perform EPB calibration using scan tool
    With the scan tool still connected, exit EPB service mode. Follow the scan tool's prompts to perform the electronic parking brake actuator calibration/learn procedure. This typically involves commanding the actuator through multiple apply and release cycles. The system must complete this calibration successfully or the parking brake will not function properly. Monitor for any fault codes during calibration.
    ⚠️EPB calibration MUST be completed successfully. Do not operate vehicle if calibration fails or fault codes are present. Seek professional diagnosis if calibration procedure does not complete.
13. 13

    Reinstall wheel and lower vehicle
    Reinstall the rear wheel onto the hub. Thread all lug nuts by hand to prevent cross-threading. Snug lug nuts in a star pattern but do not fully tighten yet. Lower the vehicle until the tire just contacts the ground but most weight is still on the jack stands. Torque the lug nuts to specification in a star pattern. Fully lower the vehicle and remove jack stands.
    Torque spec

    Wheel Lug Nuts190 Nm (140 lb-ft)
14. 14

    Repeat procedure for opposite side if needed
    If replacing both rear parking brake actuators, repeat the entire procedure for the opposite rear wheel. Both sides must be calibrated individually using the scan tool.

Reassembly

1. Verify all electrical connectors are fully seated and locked
2. Confirm all caliper mounting hardware is torqued to specification
3. Check that brake hoses have no kinks or tension
4. Verify wheel lug nuts are torqued in star pattern to specification
5. Double-check that no tools or parts remain in wheel well area

Verification

• With scan tool, verify no parking brake system fault codes are present and calibration is complete
• With vehicle on level ground and transmission in Park, test electronic parking brake by applying and releasing multiple times using the dashboard switch. Verify the indicator light responds correctly and you hear/feel the actuator engage and release
• Attempt to roll the vehicle forward and backward with parking brake applied - vehicle should not move
• Test drive vehicle at low speed in a safe area. Apply service brakes firmly several times to ensure proper brake pad seating
• After test drive, recheck parking brake operation and verify no warning lights are illuminated
• Check brake fluid level in master cylinder reservoir and top off with ACDelco DOT 4 if needed (fluid level may drop slightly during actuator cycling)
• Verify no brake fluid leaks are present at the actuator mounting area
• Re-torque wheel lug nuts after first 50-100 miles of driving

Related trouble codes on this vehicle

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