Parking Brake Actuator

This procedure replaces the electronic parking brake actuator on the rear brake caliper assembly, restoring proper electronic parking brake function.

Warnings

Tools required

Parts

• Parking brake actuator assembly × 1 — Use OEM specification - Toyota part 47750-06180 or equivalent
• Caliper mounting bolts (if corroded) × 2 — Use OEM specification
• Brake fluid DOT 3 × 1 — Use OEM specification

Fluids

• brake — 0.5 qt

Preparation

1. Park vehicle on level ground and place transmission in Park (automatic) or gear (manual)
2. Engage parking brake initially, then release it before beginning work
3. Chock the front wheels securely
4. Connect OBD-II scan tool and verify communication with brake system
5. Using scan tool, navigate to parking brake service mode and retract the parking brake actuator pistons completely - this is ESSENTIAL before removal
6. Disconnect negative battery terminal and wait 3 minutes to discharge airbag system capacitors
7. Loosen rear wheel lug nuts while vehicle is on ground
8. Raise rear of vehicle and support securely on jack stands at manufacturer-specified jacking points
9. Remove rear wheels completely
10. Siphon some brake fluid from master cylinder reservoir to prevent overflow when compressing caliper piston (do not let level drop below MIN line)

Procedure

1. 1

   Identify and access parking brake actuator
   Locate the parking brake actuator on the rear of the brake caliper. It is a cylindrical motor assembly with an electrical connector. Clean the area around the actuator and caliper with brake cleaner to remove dirt and debris. Spray penetrating oil on the actuator mounting bolts and allow to soak for 5-10 minutes.
2. 2

   Disconnect actuator electrical connector
   Locate the electrical connector on the parking brake actuator. Press the locking tab and carefully disconnect the connector. Inspect connector pins for corrosion or damage. Do not pull on wires - support the connector body while disconnecting.
3. 3

   Remove actuator mounting bolts
   Using appropriate socket, remove the two mounting bolts securing the parking brake actuator to the rear brake caliper body. Note the bolt locations and any washers or spacers. The actuator should now be loose but may be held by corrosion or the internal mechanism. Gently wiggle and pull the actuator away from the caliper body. If resistance is felt, verify the actuator was properly retracted using the scan tool.
   ⚠If the actuator was not properly retracted, it may be under pressure and difficult to remove. Do NOT force it. Return to scan tool and verify retraction procedure was completed.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
4. 4

   Inspect caliper spindle and seals
   With actuator removed, inspect the caliper spindle (the shaft that the actuator drives) for damage, corrosion, or seized condition. The spindle should rotate freely by hand. Inspect the O-ring seal on the actuator mounting surface. Clean the mounting surface thoroughly with brake cleaner. If spindle is seized or damaged, the entire caliper assembly requires replacement.
5. 5

   Prepare new parking brake actuator
   Remove new actuator from packaging. Verify it matches the original part by comparing physical dimensions and electrical connector. Inspect the new actuator for any shipping damage. Ensure the actuator is in the retracted position - if not, connect it temporarily to the vehicle harness with scan tool active and retract before installation. Apply a thin coating of silicone brake grease to any O-ring seals if present.
6. 6

   Install new parking brake actuator
   Align the new actuator with the caliper spindle, ensuring proper engagement of the internal drive mechanism. The actuator should slide smoothly onto the caliper body. If resistance is encountered, verify alignment and that the spindle is in the correct rotational position. Do not force. Insert mounting bolts with any original washers or spacers in their correct positions. Apply medium-strength thread locker to bolt threads.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
7. 7

   Torque actuator mounting bolts
   Using a calibrated torque wrench, tighten the parking brake actuator mounting bolts to specification in a cross pattern (alternate between bolts). Verify the actuator is seated flush against the caliper body with no gaps.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
8. 8

   Reconnect electrical connector
   Reconnect the electrical connector to the parking brake actuator. Ensure the connector locks into place with an audible click. Gently tug on the connector to verify it is secure. Route any wiring away from moving parts and heat sources.
9. 9

   Check brake pad position and caliper function
   Before reinstalling wheel, verify brake caliper slides freely on its mounting pins. Push the caliper piston inward using a brake caliper tool or large C-clamp to accommodate brake pad wear. Apply pressure slowly and watch the master cylinder reservoir - stop if fluid reaches MAX line. The piston should compress smoothly without excessive force.
10. 10

    Reinstall wheel and lower vehicle
    Reinstall the rear wheel, threading lug nuts by hand to prevent cross-threading. Snug lug nuts in a star pattern but do not fully torque yet. Repeat entire procedure on opposite side if replacing both actuators (recommended for even wear). Lower vehicle until wheels just contact ground but suspension is not fully loaded. Torque wheel lug nuts to specification in a star pattern.
    Torque spec

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

    Reconnect battery and initialize system
    Reconnect negative battery terminal. Turn ignition to ON position without starting engine. Using the scan tool, exit parking brake service mode and perform parking brake actuator initialization procedure. This will calibrate the new actuator and set proper piston position. Follow all scan tool prompts. The procedure may take 2-3 minutes and you will hear the actuators cycling.
12. 12

    Bleed brake system if required
    Check brake fluid level in master cylinder reservoir and top off with fresh DOT 3 brake fluid to MAX line. If any brake lines were loosened or air may have entered the system, perform brake bleeding procedure starting with the wheel furthest from the master cylinder. For this repair without line disconnection, bleeding is typically not required but pump brake pedal several times to seat components.
    ⚠If brake pedal feels soft or spongy after installation, the system MUST be bled before driving. A soft pedal indicates air in the system and will result in reduced braking performance.

Reassembly

1. Verify all mounting bolts are torqued to specification
2. Confirm electrical connectors are fully seated and locked
3. Check that no tools or parts were left in wheel well area
4. Verify brake fluid level is between MIN and MAX marks with fresh DOT 3 fluid
5. Ensure all wheels are installed and lug nuts torqued in star pattern

Verification

• With engine running, apply and release electronic parking brake using dashboard switch - verify you hear actuator motors operating and see dashboard indicator illuminate/extinguish properly
• Park on a moderate incline (if safe area available), set parking brake, release foot brake, and verify vehicle is held securely by parking brake alone
• Drive vehicle in safe area at low speed (5-10 mph) and apply service brakes - verify firm pedal feel and straight stops with no pulling to either side
• Test service brakes at moderate speeds (up to 25 mph) with progressively harder applications - verify normal brake function without noise, vibration, or warning lights
• Using scan tool, check for any parking brake system fault codes - clear any codes related to initialization and verify they do not return
• Verify parking brake warning light extinguishes completely when brake is released and illuminates when applied
• After first 50-100 miles of driving, re-check actuator mounting bolt torque and wheel lug nut torque
• If ANY abnormal brake behavior is observed, do NOT drive the vehicle - seek professional service immediately

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