Automobile & Light Truck Certification Test A5 BrakesDisc Brake Diagnosis and RepairEasy
A vehicle owner complains that their parking brake handle requires excessive effort to engage and still does not hold the vehicle securely. The technician visually inspects the cables and finds no obvious damage. What is the MOST likely cause of this condition?
- AA seized front brake caliper.
- BStretched parking brake cables.
- COver-adjusted rear service brake shoes.
- DContaminated parking brake shoes.
Show answer & explanationAnswer & explanation
Correct answer: B. Stretched parking brake cables.
Over time and with use, parking brake cables can stretch. When a cable stretches, more lever travel (and thus more effort) is required to achieve the same amount of tension, and even then, the system may not apply enough force to hold the vehicle securely.
Why the other options are wrong
- A. A seized front brake caliper would cause dragging service brakes, but would not affect the parking brake's effort or holding ability.
- C. Over-adjusted rear service brake shoes (if it's a drum brake or hat-type system) would make the parking brake engage very easily with little travel, not require excessive effort.
- D. Contaminated parking brake shoes would reduce friction, leading to poor holding power, but would not necessarily increase the effort required at the handle; rather, the handle might feel 'normal' but the brake would just slip.
Parking Brake Cable Stretch
The elongation of a parking brake cable over time due to repeated use and stress, leading to increased lever travel, higher effort required to apply, and reduced holding force.
- Common wear item.
- Increases cable slack.
- Requires adjustment or replacement.
Memory trick: Cable long, grip bad, adjust or replace, don't be sad.