Automotive and Mechanics Brake Systems 2

Question 1

The 'discard dimension' stamped on a brake rotor indicates which specification?

Accepted Answer

The minimum thickness at which the rotor must be discarded

Answer

The discard dimension is the minimum allowable thickness; rotors worn or machined below this spec must be replaced as they cannot safely dissipate braking heat.

Question 2

A spongy or soft brake pedal that gradually sinks toward the floor most likely indicates which condition?

Accepted Answer

Air trapped in the hydraulic brake lines

Answer

Air is compressible unlike brake fluid, so air trapped in the lines creates a soft, spongy pedal feel and reduces hydraulic pressure transfer.

Question 3

Which tool is most commonly used to retract a disc brake caliper piston when installing new brake pads?

Accepted Answer

C-clamp or dedicated caliper piston tool

Answer

A C-clamp or dedicated caliper piston tool compresses the piston back into its bore to create clearance for the thicker new brake pads.

Question 4

When bleeding brakes on a four-wheel vehicle using the gravity or pressure method, which wheel is typically bled FIRST?

Accepted Answer

Rear right (furthest from master cylinder on most vehicles)

Answer

The standard sequence starts at the wheel furthest from the master cylinder—typically the rear right—to push air progressively through the entire system.

Question 5

What energy source does a conventional vacuum-assisted brake booster use to multiply the driver's pedal effort?

Accepted Answer

Engine intake manifold vacuum

Answer

A vacuum brake booster uses the low pressure (vacuum) from the engine's intake manifold to create a pressure differential across a diaphragm that amplifies pedal force.

Automotive and Mechanics Practice Test

Automotive and Mechanics Practice Test

Automotive and Mechanics Brake Systems 2