Braking Systems Questions and Answers

Answer: C

A locked rear axle generates no lateral force, so the rear swings and the vehicle spins. It is precisely why proportioning valves exist and why front bias is universal. Front lock merely produces understeer and a straight slide. A symptom that appears under one condition and not another is what narrows the diagnosis quickly. Working the distinction through on a single concrete case fixes it more firmly than any rule of thumb.

Answer: D

Locked front wheels cannot steer, so the vehicle ploughs on in a straight line, which is undesirable but stable. Rear lock produces the spin. That asymmetry is why front bias is always chosen. The order in which the effects act is what decides the outcome, so it is worth establishing first. A symptom that appears under one condition and not another is what narrows the diagnosis quickly.

Answer: A

Deceleration is quoted as a fraction of g, and a good road car achieves close to one g on dry tarmac. Distance is derived from it and from the initial speed. Both figures appear in regulations for different purposes. Checking which component actually carries the load settles most questions of this kind at once. The order in which the effects act is what decides the outcome, so it is worth establishing first.

Answer: B

Tread depth governs the ability to clear water, and a worn tyre aquaplanes at a much lower speed. Pressure and age both matter as well, which makes those options genuine secondary factors. The braking system cannot exceed what the tyre transmits. Tracing the requirement back to the physical constraint that produces it makes the answer follow. Checking which component actually carries the load settles most questions of this kind at once.

Answer: C

However powerful the brake, the vehicle cannot decelerate faster than the tyre can transmit force to the road. Bigger brakes buy fade resistance rather than a shorter first stop. Heat dissipation limits repeated stops, which is a real but different constraint. The shared behaviour explains why these belong together and the differences explain why both exist. Tracing the requirement back to the physical constraint that produces it makes the answer follow.

Answer: D

The rear axle carries less weight under braking, so its wheels lock at a lower pressure and must be limited to keep the vehicle stable. The reason therefore explains the assertion, and rear lock is the instability that the valve exists to prevent. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision. The shared behaviour explains why these belong together and the differences explain why both exist.

Answer: A

Fixed calipers do use opposed pistons, but a sliding caliper depends on its slides moving freely and any stiffness makes the piston side pad wear faster. Uneven wear is the characteristic sliding caliper complaint. Reading the definition literally, rather than recalling a summary, avoids the usual confusion. Naming the cost of a choice alongside its benefit is what turns a fact into a design decision.

Answer: B

A firm pedal needing high effort is the signature of a failed servo or its vacuum supply. Glazing also reduces effectiveness, which makes it a genuine alternative worth checking, but the high effort points to the assistance. Most errors here come from carrying across a result from a neighbouring case where it does not hold. Reading the definition literally, rather than recalling a summary, avoids the usual confusion.

Answer: C

The servo multiplies the driver's effort and exists on vehicles with no anti-lock system at all. Sensors, modulator and controller are the three anti-lock elements. Knowing which parts belong to which system speeds up diagnosis. Naming what changes and what stays the same is the reliable route through questions of this shape. Most errors here come from carrying across a result from a neighbouring case where it does not hold.

Answer: D

The one way valve in the servo hose holds the vacuum so one or two assisted applications remain available after the engine has stopped. Its failure is detected by the immediate loss of that reserve. Working the distinction through on a single concrete case fixes it more firmly than any rule of thumb. Naming what changes and what stays the same is the reliable route through questions of this shape.