Pinpoint Test B: The Parking Brake Will Not Release

Parking Brake

Pinpoint Test B: The Parking Brake Will Not Release

Normal Operation

When the parking brake control is fully applied and the pedal is pressed a second time, the ratchet mechanism and return spring in the parking brake control cause the tension on the parking brake cables to release. The springs on both rear parking brake cables and the spring on the equalizer provide the force necessary to return the system to the released position.

This pinpoint test is intended to diagnose the following:

- Parking brake cables

- Parking brake control

- Rear brake caliper

PINPOINT TEST B : THE PARKING BRAKE WILL NOT RELEASE

B1 CHECK THE PARKING BRAKE CONTROL

- Press the parking brake control pedal.

Does the parking brake control move?

Yes
GO to B3.

No
GO to B2.

B2 ISOLATE THE PARKING BRAKE CONTROL

- Release the parking brake cable tension at the parking brake control adjusting nut.

- Disconnect the parking brake cable at the parking brake lever.

- Press the parking brake control pedal.

Does the parking brake control move?

Yes
GO to B3.

No
INSTALL a new parking brake control. REFER to Parking Brake Control . TEST the system for normal operation.

B3 ISOLATE THE FRONT PARKING BRAKE CABLE

- Disconnect the return spring from the equalizer.

- If necessary, relieve the tension in the parking brake cable by loosening the equalizer adjustment nut until the rear cables can be disconnected from the equalizer.

- Disconnect the LH and RH cables from the equalizer.

- Verify that the front cable can slide freely in the conduit.

Does the cable slide freely in the conduit?

Yes
GO to B4.

No
INSTALL a new front cable. REFER to Parking Brake Cable - Front . TEST the system for normal operation.

B4 ISOLATE THE REAR PARKING BRAKE CABLES

- Disconnect the LH and RH parking brake cables from the brake calipers.






- While holding the cable conduit, attempt to slide the LH and the RH cables inside their conduits.

Do the cables slide freely inside their conduits?

Yes
INSTALL new rear brake caliper(s). ADJUST the parking brake cable. REFER to Parking Brake Cable Adjustment .

No
INSTALL new rear brake cable(s). REFER to Parking Brake Cable - Rear, LH and/or Parking Brake Cable - Rear, RH . TEST the system for normal operation.