Pinpoint Test A: The Parking Brake Does Not Apply

Parking Brake






Pinpoint Tests

Pinpoint Test A: The Parking Brake Does Not Apply

Normal Operation

When the parking brake control pedal is pressed, the pedal should move a short distance, with more pressure needed to apply the pedal as it gets closer to the floor, until the parking brake is fully applied. When the parking brake control is pressed, tension is applied to the intermediate parking brake cable. This tension pulls on the RH rear parking brake cable, which is attached to the RH rear parking brake actuator, and applies the RH rear brake caliper. At the same time, the tension in the intermediate cable causes the intermediate cable conduit to attempt to straighten out. This straightening effect causes tension that pulls the LH rear cable, which is attached to the LH rear parking brake actuator, and applies the LH rear brake caliper.

This pinpoint test is intended to diagnose the following:
- Front parking brake cable and conduit
- Intermediate parking brake cable and conduit
- Parking brake control
- Rear parking brake cables and conduits
- Rear brake calipers



PINPOINT TEST A: THE PARKING BRAKE DOES NOT APPLY

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A1 CHECK THE PARKING BRAKE CONTROL


- Press the parking brake control pedal.
- Does the parking brake control move?

Yes
GO to A2.

No
GO to A3.

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A2 CHECK FOR BROKEN CABLES


- NOTE: Have an assistant press and release the parking brake pedal to help isolate disconnected cables or cables that do not move.
- Inspect the following items for damage and correct connections:
- Parking brake control
- Front cable
- Intermediate cable
- LH rear cable
- RH rear cable
- Cable equalizers
- Rear brake caliper actuators
- Is any damage found or are any components disconnected?

Yes
CONNECT the component(s) or INSTALL new parking brake component(s) as necessary. TEST the system for normal operation.

No
VERIFY that the rear pads are within thickness specifications. If the rear pads are OK, INSTALL new rear brake calipers.

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A3 ISOLATE THE PARKING BRAKE CONTROL AND FRONT PARKING BRAKE CABLE


- Disconnect the front cable from the intermediate cable at the cable union.




- Press the parking brake control pedal.
- Does the parking brake control pedal move?

Yes
GO to A4.

No
GO to A6.

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A4 ISOLATE THE INTERMEDIATE PARKING BRAKE CABLE


- Disconnect the LH and RH cables from the intermediate cable equalizer.
- While holding the intermediate cable conduit, attempt to slide the intermediate cable inside the conduit.
- Does the cable slide freely inside the conduit?

Yes
GO to A5.

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

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A5 ISOLATE THE REAR PARKING BRAKE CABLES


- Disconnect the LH and RH parking brake cables from the subframe brackets and the brake calipers.
- While holding the cable conduit, attempt to slide the cable inside the conduit.
- Does the cable slide freely inside the conduit?

Yes
INSTALL new rear brake calipers.

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

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A6 ISOLATE THE FRONT PARKING BRAKE CABLE


- Disconnect the front parking brake cable and conduit from the parking brake control.
- While holding the cable conduit, attempt to slide the cable inside the conduit.
- Does the cable slide freely inside the conduit?

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

No
INSTALL a new front parking brake cable. TEST the system for normal operation.

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