Automobile & Light Truck Certification Test A5 BrakesDrum Brake Diagnosis and RepairMedium
A vehicle owner reports that their parking brake feels very loose and barely holds the vehicle on an incline. During inspection, the technician confirms excessive parking brake cable slack. After ensuring the rear drum brakes are correctly adjusted and in good condition, what is the MOST appropriate next step?
- AReplace the parking brake shoes.
- BAdjust the parking brake cable at the equalizer or adjusting nut.
- CBleed the hydraulic brake system.
- DLubricate the parking brake levers at the backing plate.
Show answer & explanationAnswer & explanation
Correct answer: B. Adjust the parking brake cable at the equalizer or adjusting nut.
If the drum brakes themselves are correctly adjusted and in good condition, and the parking brake cable has excessive slack, the most direct solution is to adjust the cable tension. Most vehicles have an adjusting nut, often at the equalizer, to take up this slack and restore proper parking brake function. Replacing shoes or bleeding the hydraulic system would not address cable slack.
Why the other options are wrong
- A. Parking brake shoes would only need replacement if worn or contaminated, not just for cable slack, especially if the service brakes are confirmed good.
- C. Bleeding the hydraulic system affects the service brakes, not the mechanical parking brake cable tension.
- D. Lubricating levers might help with binding, but it won't take up excessive cable slack.
Parking Brake Cable Adjustment
The procedure to set the correct tension and engagement point of the parking brake cable, ensuring it holds the vehicle securely without causing drag.
- Performed after drum brake service or if cable slack is excessive.
- Typically involves an adjusting nut at the equalizer or cable end.
- Critical for safety and proper parking brake function.
Memory trick: Loose parking brake? Find the adjuster, make it tight, for safety's sake.