Technician A says that disc brakes are self adjusting and the brake pedal height should not become lower as the disc brake pads wear. Technician B says that as the disc brake pads wear, the level of brake fluid in the master cylinder reservoir drops. Which technician is correct?a. Technician A only
b. Technician B only
c. Both Technicians A and B
d. Neither Technician A nor B

c. Both Technicians A and B

Explanation:

Disc brakes are self-adjusting because the pistons in the brakes are much larger in diameter than the ones in the master cylinder. If the brake pistons retracted into their cylinders, it might take several applications of the brake pedal to pump enough fluid into the brake cylinder to engage the brake pads.  The height of the brake pedal is also necessary because if they become lower the disc brake pads will wear, this is why self-adjustment is important and disc brake pads usually have a piece of metal on them called a wear indicator to warn of wearing. Also when disc break pads wear, the fluid level in the master cylinder drops, armed with this knowledge of low master cylinder fluid level one can inspect the disc pads for wear.  Thus both Technicians A and B are correct.

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