Parking Brake Actuator

Replace the electronic parking brake (EPB) actuator on a 2024 Model S Long Range AWD. The EPB actuators are integrated into the rear calipers, so this job involves retracting the actuator electronically, removing it from the caliper body, and installing the new unit.

Warnings

Tools required

Parts

• Rear parking brake actuator (left or right, as applicable) × 1 — OEM Tesla Model S rear EPB actuator — verify by VIN
• Actuator-to-caliper O-ring / seal (if supplied separately) × 1 — OEM specification
• Caliper bracket bolts (if reuse not permitted) × 2 — OEM specification — single-use if so designated

Fluids

• DOT 3 Brake Fluid (top-off only if system opened) — 0.25 qt

Preparation

1. Park on level ground, place in P, engage parking brake.
2. Exit ALL doors with the key fob away from the vehicle. Wait at least 2 minutes for HV systems to fully de-energize, even on this non-HV job.
3. Place the EPB into service/maintenance mode via the touchscreen (Service menu) so the actuator fully retracts BEFORE disconnecting 12V power. This is critical — once 12V is removed you cannot command the actuator.
4. Disconnect the 12V low-voltage battery in the front trunk (frunk) under the nose cowl panel. For 2021+ Plaid variants with 16V Li-ion under the rear seat, disconnect that unit instead — verify by VIN.
5. DO NOT touch, cut, or pierce ANY orange cable — these are high-voltage and lethal.
6. If at any point you encounter an orange cable, an HV component, or are unsure if a system is de-energized: STOP and consult a Tesla-certified technician.
7. Loosen rear lug nuts while wheels are on the ground.
8. Lift the rear of the vehicle using Tesla-specified jack pad locations and support on rated jack stands. Confirm the vehicle is stable before working underneath.
9. Remove the rear wheel(s) on the side(s) being serviced.

Procedure

1. 1

   Confirm EPB is fully retracted
   Visually verify the EPB actuator piston is fully retracted at the rear caliper. If 12V was disconnected before service mode was engaged, do NOT proceed — restore 12V, wake the vehicle, command retraction via the touchscreen, then disconnect 12V again.
   ⚠️Attempting to remove a non-retracted EPB actuator can damage the caliper and cause injury from spring-loaded release.
2. 2

   Disconnect EPB actuator harness
   Locate the electrical connector at the rear of the EPB actuator on the caliper. Release the connector lock tab and unplug. Inspect the connector and pigtail for corrosion or damage; report findings if reusing.
3. 3

   Support the caliper (if removal required)
   On most Model S rear calipers, the EPB actuator can be removed without unbolting the caliper from its bracket. If access is restricted, remove the caliper slide pin bolts and suspend the caliper from the suspension with a hanger — do NOT let it hang by the flexible brake hose.
   ⚠Never allow the caliper to hang by the brake hose; internal damage to the hose can cause future failure.
   Torque spec

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

   Remove EPB actuator fasteners
   Remove the bolts (typically Torx) securing the EPB actuator housing to the rear of the caliper body. Note the orientation of the actuator and the location of any wiring routing clips.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
5. 5

   Remove the actuator from the caliper
   Pull the actuator straight back from the caliper body. Expect minor resistance from the seal. Inspect the drive splines and the caliper-side gear/spindle for damage, debris, or moisture intrusion. Clean the mating surfaces with brake cleaner and a lint-free rag.
   ⚠If brake fluid is observed leaking from the caliper bore behind the actuator, the caliper itself is failed and must be replaced — do not simply install a new actuator.
6. 6

   Prepare new actuator
   Compare the new actuator side-by-side with the old unit (drive coupler shape, electrical connector keying, mounting bolt pattern). Confirm the new O-ring/seal is seated. Apply a light film of silicone brake grease to the drive coupler if specified by the manufacturer instructions included with the part.
7. 7

   Install new EPB actuator
   Align the actuator drive coupler to the caliper spindle and seat the actuator flush against the caliper body. Do not force — if it will not seat, the spindle is not in the retracted/aligned position. Hand-thread both fasteners before final torque to avoid cross-threading.
   Torque spec

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

   Torque actuator fasteners
   Torque the actuator mounting bolts to specification. Do not overtighten — the housing is alloy and threads are in alloy.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
9. 9

   Reconnect electrical harness
   Reconnect the EPB harness connector and confirm the lock tab clicks home. Reseat any wiring clips removed earlier so the harness is not contacting the rotor, hub, or suspension link.
10. 10

    Reinstall caliper (if removed)
    If the caliper was removed from its slide pins or bracket, reinstall and torque the slide pin bolts, applying silicone brake grease as noted. If the caliper bracket itself was removed, torque caliper bracket bolts to spec with threadlocker.
    ℹ️Front caliper bracket torque is listed for reference only — this job is rear-axle. Verify the rear caliper bracket torque against the Tesla Service Manual before final assembly.
    Torque spec

    Caliper Slide Pin Bolts35 Nm (26 lb-ft)

    Caliper Bolts88 Nm (65 lb-ft)

    Bracket Bolts102 Nm (75 lb-ft)

Reassembly

1. Reinstall the rear wheel and hand-snug the lug nuts in a star pattern.
2. Lower the vehicle to the ground.
3. Final-torque the lug nuts in a star pattern to specification.
4. Reconnect the 12V (or 16V) low-voltage battery and secure the terminal.
5. Close the frunk (or rear seat access panel for 16V) and allow the vehicle to fully wake — this can take 1–2 minutes.
6. Enter Service Mode via the touchscreen and exit EPB maintenance/service mode. Run the EPB calibration / actuator learn routine as prompted.
7. Cycle the parking brake several times via the touchscreen and confirm normal apply/release without warning messages.

Verification

• Confirm no EPB-related alerts appear on the instrument cluster or touchscreen after a full wake cycle.
• With the vehicle on level ground, apply the parking brake from the touchscreen — listen for normal actuator sound on both rear corners and verify the rear wheels lock.
• Release the parking brake and confirm the rear wheels rotate freely with no drag.
• Perform a low-speed roll test (5–10 mph in a safe area) and apply the EPB via the touchscreen 'emergency' function only if needed to confirm dynamic operation. Otherwise, a static apply/release cycle is sufficient.
• Re-check actuator mounting bolts after the first 50 miles for any loosening.
• Note: Tesla recommends brake fluid replacement every 2 years regardless of mileage. If the fluid is at or beyond that interval, schedule a brake fluid service. Tesla also recommends rear drive unit gear oil inspection at 12,500 mi initial and 25,000–50,000 mi thereafter — not 'lifetime.'

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