Parking Brake Actuator

Replace the electronic parking brake actuator (motor) on the rear brake caliper assembly to restore parking brake function.

Warnings

Tools required

Parts

• Electronic parking brake actuator motor × 1 — Motorcraft BRM-341 or equivalent
• Brake fluid (for topping off) × 1 — Use Motorcraft DOT 4 LV

Fluids

• Motorcraft DOT 4 LV Brake Fluid — 0.5 qt

Preparation

1. Ensure vehicle is on level ground with transmission in Park
2. Verify battery voltage is at least 12.4V; charge if necessary
3. Place wheel chocks in front of front wheels
4. Loosen rear wheel lug nuts while vehicle is on ground (do not remove)
5. Raise rear of vehicle and support securely on jack stands at frame contact points
6. Remove rear wheels completely
7. Clean brake caliper area with brake cleaner to identify actuator location

Procedure

1. 1

   Connect scan tool and enter EPB service mode
   Connect OBD-II scan tool to diagnostic port under driver side dash. Navigate to EPB service functions and select 'Retract EPB Caliper' or 'Service Mode'. Follow scan tool prompts to fully retract the electronic parking brake actuator motor. You should hear the motor running and the caliper piston retracting. Wait for scan tool to confirm retraction is complete before proceeding.
   ⚠️Do not disconnect scan tool or turn off ignition until service mode is properly exited at job completion. Loss of power during service can lock actuator in unsafe position.
2. 2

   Remove brake caliper from bracket
   Locate the two caliper slide pin bolts on the rear of the caliper assembly. Remove both slide pin bolts completely. Carefully pivot the caliper assembly upward and off the brake rotor. Support the caliper with a bungee cord or wire tied to the suspension - do not let it hang by the brake hose.
   ⚠Never allow brake caliper to hang by the flexible brake hose. This can damage internal hose structure and cause brake failure.
   Torque spec

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

   Disconnect EPB actuator electrical connector
   Locate the electrical connector on the parking brake actuator motor mounted to the rear of the caliper. Press the locking tab and carefully disconnect the wiring harness. Inspect connector for corrosion or damage; clean with electrical contact cleaner if necessary.
   ⚠Do not pull on wires - press release tab and pull on connector body only to prevent wire damage.
4. 4

   Remove parking brake actuator motor
   Locate the two mounting bolts securing the EPB actuator motor to the rear brake caliper body. Remove both bolts completely. Carefully rotate and pull the actuator motor assembly straight away from the caliper. Note the orientation of the actuator drive gear and caliper interface for reinstallation. Inspect the caliper piston screw mechanism for damage or excessive wear.
   Torque spec

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

   Inspect caliper piston and seal
   Examine the caliper piston screw mechanism where the actuator interfaces. Check for rust, corrosion, or damaged threads. Inspect the rubber seal/boot around the actuator mounting area for cracks or deterioration - replace caliper if seal is damaged. Clean the mounting surface with brake cleaner and wire brush, ensuring no debris remains in the screw mechanism.
   ℹ️If piston screw mechanism shows significant wear or damage, the entire caliper assembly should be replaced rather than just the actuator.
6. 6

   Install new parking brake actuator
   Apply a thin film of silicone brake grease to the actuator drive gear (not to mounting surfaces). Align the new actuator motor with the caliper mounting holes, ensuring the drive gear properly engages the piston screw mechanism. Hand-thread both mounting bolts to prevent cross-threading. Torque mounting bolts to specification in a cross pattern.
   ⚠Ensure actuator drive gear is properly seated in piston screw mechanism before tightening bolts. Improper alignment can strip gears during operation.
   Torque spec

   Mounting Bolts34 Nm (25 lb-ft)
7. 7

   Reconnect electrical connector
   Reconnect the electrical connector to the parking brake actuator motor, ensuring it clicks securely into place. Gently tug on connector to verify it is locked. Route wiring harness away from any moving parts or heat sources.
8. 8

   Reinstall brake caliper assembly
   Remove support wire/bungee cord from caliper. Before reinstalling, ensure brake pads are still properly positioned in caliper bracket. If caliper piston extended during service, use caliper piston tool to carefully retract it while actuator is in service mode. Apply silicone brake grease to slide pin bolts and their boots. Position caliper over brake rotor and bracket, aligning slide pin bolt holes. Install and hand-thread both slide pin bolts, then torque to specification.
   ⚠Do not force caliper into position. If piston prevents installation, it must be retracted using proper tool while EPB is in service mode.
   Torque spec

   Caliper Slide Pin Bolts35 Nm (26 lb-ft)
9. 9

   Exit EPB service mode and calibrate
   Using the scan tool, select 'Exit Service Mode' or 'Calibrate EPB'. Follow all scan tool prompts to run the EPB calibration procedure. The actuator motor will extend and retract several times during calibration. Wait for scan tool to confirm calibration is successful before proceeding. Clear any diagnostic codes if prompted.
   ⚠️Do not skip calibration procedure. Uncalibrated EPB may not apply with sufficient force or may fail to release, creating dangerous driving conditions.
10. 10

    Reinstall wheel and lower vehicle
    Reinstall rear wheel, hand-threading all lug nuts. Lower vehicle until wheel just contacts ground but vehicle weight is still on jack stands. Torque lug nuts to specification in a star pattern. Fully lower vehicle and remove jack stands. Re-torque lug nuts in star pattern with vehicle on ground.
    Torque spec

    Wheel Lug Nuts140 Nm (103 lb-ft)
11. 11

    Check brake fluid level
    Open hood and locate brake fluid reservoir. Check fluid level - it should be between MIN and MAX marks. If low, top off with Motorcraft DOT 4 LV brake fluid only. Do not overfill. Wipe any spilled fluid immediately to prevent paint damage.
    ⚠Use only DOT 4 LV brake fluid specified for this vehicle. Mixing fluid types can cause brake system failure.

Reassembly

1. Repeat procedure for opposite side if replacing both actuators
2. Ensure all electrical connectors are fully seated and locked
3. Verify no tools or parts were left in wheel well area
4. Double-check all lug nuts are torqued to specification

Verification

• With engine running, apply and release electronic parking brake using dash switch - verify smooth operation with no unusual noises
• Park on slight incline, apply EPB, shift to neutral - verify vehicle is held securely
• Release EPB and verify indicator light extinguishes on instrument cluster
• Drive vehicle slowly in safe area and apply service brakes - verify normal pedal feel and stopping power
• Check scan tool for any new EPB-related diagnostic codes; address any codes before returning to service
• Verify parking brake warning light does not illuminate during normal driving
• Re-check brake fluid level after test drive; top off if necessary

More procedures for this vehicle