Parking Brake Actuator

Replace the electronic parking brake actuator motor on the rear brake calipers, requiring caliper removal and brake system work.

Warnings

Tools required

Parts

• Electronic parking brake actuator motor × 1 — Use OEM specification
• Brake caliper mounting hardware kit × 1 — Use OEM specification
• Brake fluid × 1 — DOT 4 Racing

Fluids

• DOT 4 Racing Brake Fluid — 1 qt

Preparation

1. Park vehicle on level surface and engage parking brake (if functional).
2. Ensure battery is fully charged as electronic parking brake service mode will draw significant power.
3. Connect OBD-II scan tool and verify communication with electronic parking brake system.
4. Loosen rear wheel lug nuts 1/4 turn while vehicle is on ground.
5. Lift rear of vehicle and secure on jack stands at manufacturer-approved lift points.
6. Remove rear wheels completely.
7. Place brake fluid catch container under work area.

Procedure

1. 1

   Enter parking brake service mode
   Using the OBD-II scan tool with EPB (Electronic Parking Brake) service function, navigate to the parking brake service menu. Select the option to retract the parking brake actuator into service mode. The actuator motor will retract the piston fully into the caliper. Verify that the actuator completes the retraction cycle and the scan tool indicates service mode is active. This step is critical and cannot be performed manually.
   ⚠️Do not attempt to remove caliper without first retracting actuator using scan tool. Manual retraction will damage the actuator and may cause sudden piston movement.
2. 2

   Disconnect brake line from caliper
   Clean the brake line fitting and surrounding area with brake cleaner. Using a line wrench to prevent rounding, loosen and remove the brake line fitting from the rear of the caliper. Immediately cap or plug the brake line and caliper port to prevent fluid loss and contamination. Position catch container to capture residual brake fluid.
   ⚠Brake fluid will drain from line and caliper. Keep away from painted surfaces and skin.
   Torque spec

   Line Fittings22 Nm (16 lb-ft)
3. 3

   Remove caliper mounting bolts
   Locate the two caliper slide pin bolts securing the caliper to the bracket. Using appropriate socket, remove both caliper slide pin bolts. Support the caliper weight as you remove the second bolt. Carefully lift the caliper off the brake rotor and set aside on a clean surface. Do not allow caliper to hang by brake line (already disconnected).
   Torque spec

   Caliper Slide Pin Bolts35 Nm (26 lb-ft)
4. 4

   Remove parking brake actuator motor
   With caliper removed and on work surface, locate the electronic parking brake actuator motor on the rear of the caliper body. It is typically secured by 2-3 Torx bolts. Using appropriate Torx bit, remove the actuator mounting bolts. Carefully separate the actuator from the caliper body, noting the position of any O-rings or seals. The actuator spindle will disengage from the caliper piston mechanism.
5. 5

   Inspect caliper piston mechanism
   With actuator removed, inspect the caliper piston and internal spindle mechanism for wear, damage, or corrosion. Check O-ring grooves on caliper body for damage. If piston or internal mechanism shows damage, the entire caliper should be replaced rather than just the actuator. Clean the actuator mounting surface with brake cleaner and wire brush if necessary.
6. 6

   Install new parking brake actuator
   Install new O-ring or seal on actuator body if included with new part. Align the actuator spindle with the caliper piston mechanism, ensuring proper engagement. Carefully install the actuator onto the caliper body, rotating slightly if needed to engage the spindle teeth. Install mounting bolts and torque to specification per service manual (typically 10-15 Nm, but verify with Maserati documentation as this is not in provided torque specs).
   ⚠Ensure actuator spindle fully engages with piston mechanism before tightening bolts. Partial engagement will cause actuator failure.
7. 7

   Reinstall caliper to bracket
   Apply silicone brake grease to caliper slide pin bolts as specified. Position caliper over brake rotor and align with bracket mounting points. Install both caliper slide pin bolts and torque in sequence to specification. Ensure caliper moves freely on slide pins.
   Torque spec

   Caliper Slide Pin Bolts35 Nm (26 lb-ft)
8. 8

   Reconnect brake line
   Remove caps or plugs from brake line and caliper port. Thread brake line fitting into caliper port by hand to avoid cross-threading. Using line wrench, torque brake line fitting to specification. Ensure fitting is properly seated and not cross-threaded.
   Torque spec

   Line Fittings22 Nm (16 lb-ft)
9. 9

   Bleed brake system
   Fill brake fluid reservoir to MAX line with DOT 4 Racing brake fluid. Using brake bleeder kit or pressure bleeder, bleed the rear brake circuit starting with the wheel furthest from master cylinder. Open bleeder screw and allow fluid to flow until all air bubbles are purged and fluid runs clear. Close bleeder screw to specification. Repeat for affected wheel. Pump brake pedal several times and verify firm pedal feel. Recheck reservoir level.
   ⚠️Air in brake lines will cause brake failure. Ensure all air is completely purged before operating vehicle.
   Torque spec

   Bleeder Screw10 Nm (7 lb-ft)
10. 10

    Calibrate parking brake actuator
    Using scan tool, exit service mode and initiate parking brake actuator calibration procedure. The actuator will extend and retract through its full range to set reference positions. This process typically takes 30-60 seconds. Scan tool will indicate when calibration is complete. Verify no error codes are present in parking brake system.
    ⚠️Actuator calibration is mandatory. Operating parking brake without calibration will cause malfunction and potential loss of parking brake function.
11. 11

    Reinstall wheels
    Install rear wheels and thread lug nuts by hand. Lower vehicle until tire just touches ground (still supported by jack). Torque wheel lug nuts to specification using star pattern. Fully lower vehicle and verify final torque on all lug nuts in star pattern.
    Torque spec

    Wheel Lug Nuts140 Nm (103 lb-ft)

Reassembly

1. Verify brake fluid level is between MIN and MAX marks on reservoir.
2. Ensure all tools and parts have been removed from under vehicle.
3. Check for any brake fluid leaks at caliper connection points.
4. Verify parking brake warning light is off on instrument cluster.

Verification

• With vehicle still on jack stands and in neutral, verify rear wheels rotate freely and brake releases completely.
• Using scan tool, activate electronic parking brake and verify actuator operates smoothly without unusual noise.
• Perform brake pedal test: pedal should feel firm after 2-3 pumps and not sink to floor.
• Perform parking brake hold test on incline: engage parking brake and verify vehicle remains stationary on moderate grade.
• Test drive in safe area at low speed and verify normal brake operation and parking brake function.
• After test drive, recheck brake fluid level and inspect for leaks at brake line connection.
• Clear any stored diagnostic codes and verify no new codes are present in parking brake system.
• Verify parking brake applies and releases properly using center console switch.

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