Pinpoint Test B: The Parking Brake Will Not Release And/Or Rear Brakes Drag

Parking Brake






Pinpoint Tests

Pinpoint Test B: The Parking Brake Will Not Release and/or Rear Brakes Drag

Normal Operation

When the parking brake release button is pressed and the brake control is released, the tension on the parking brake cables return the system to the released position.

This pinpoint test is intended to diagnose the following:
- Parking brake cables and conduits
- Parking brake control
- Parking brake equalizer
- Rear brake hardware
- Rear brake shoes



PINPOINT TEST B: THE PARKING BRAKE WILL NOT RELEASE AND/OR REAR BRAKES DRAG

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B1 ISOLATE THE PARKING BRAKE CONTROL


- Disconnect the rear cables from the cable equalizer.
- Does the parking brake release?

Yes
INSTALL a new parking brake control. REFER to Parking Brake Control Service and RepairTEST the system for normal operation.

No
GO to B2.

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B2 CHECK THE REAR BRAKE SHOES AND HARDWARE


- Remove the rear brake drum. Refer to Drum Brake System.
- Inspect the brake shoes, hardware and backing plate.
- Are the shoes, hardware and backing plate in good condition?

Yes
GO to B3.

No
INSTALL new components as necessary. REFER to Drum Brake System. TEST the system for normal operation.

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B3 ISOLATE THE REAR PARKING BRAKE CABLES


- Disconnect the parking brake cables from the brake shoe actuators.
- While holding the rear cable conduit, attempt to slide the rear cable inside the conduit.
- Does the rear cable slide freely inside the conduit?

Yes
The system is operating normally at this time. The concern may have been cause by a seized or binding component. CLEAN and LUBRICATE the brake backing plate using the specified materials. CONNECT all cables and INSTALL all components. TEST the system for normal operation.

No
INSTALL new rear brake cable(s). REFER to Parking Brake Cable Service and Repair. TEST the system for normal operation.

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