Final answer:
The statement that is not true about parking brakes is option a) .the disc parking brake pads are adjusted by the piston seal.
Step-by-step explanation:
In a disc parking brake system, the pads are adjusted manually by the driver or through an automatic self-adjustment mechanism. The piston seal does not play a role in adjusting the pads.
On the other hand, the other statements are true:
- b.a broken return spring on a shoe may cause the parking brake to grab. When the return spring is broken, it can cause the parking brake shoe to remain in contact with the drum, resulting in grabbing or dragging of the brake.
- c.the shoes for the auxiliary parking brakes on a four-wheel disc should be inspected each time the pads are changed. The auxiliary parking brakes on a four-wheel disc system have shoes that require inspection whenever the brake pads are changed, ensuring they are in good working condition.
- d.on a driveline parking brake, the expanding shoes are activated by levers and cams. In the case of a driveline parking brake, the expanding shoes are indeed activated by levers and cams, which expand the shoes against the inside of the drum.