Question 1

What part causes the disc brake caliper piston to retract when the brakes are released?

Accepted Answer

The square cut O-ring in the caliper is designed to twist when the piston moves out during braking and untwist to pull the piston back when the brake is released, allowing for the retraction of the piston.

Question 2

Two technicians are discussing the reason that the brake fluid level in the master cylinder drops. Technician A says that it may be normal due to the wear of the disc brake pads. Technician B says that a low brake fluid level may indicate a hydraulic leak somewhere in the system. Which technician is correct?

Accepted Answer

Both technicians are correct. Technician A is correct because as disc brake pads wear, the caliper pistons extend further, requiring more brake fluid in the caliper, which can lead to a lower fluid level in the master cylinder. Technician B is correct because a low brake fluid level can also indicate a leak in the hydraulic brake system.

Question 3

Two technicians are discussing a floating-type disc brake caliper. Technician A says that if the caliper slides are corroded, one pad may wear more than the other pad on the same wheel brake. Technician B says that if a caliper slide is corroded, reduced braking may occur. Which technician is correct?

Accepted Answer

Both technicians are correct. Corrosion on the caliper slides can cause uneven pad wear because the caliper cannot move freely to apply even pressure on both pads. This condition can also lead to reduced braking efficiency as the caliper's movement is restricted, affecting the overall braking force applied.

Question 4

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?

Accepted Answer

Both technicians are correct. Disc brakes are self-adjusting, meaning the brake pedal height should remain consistent even as the pads wear. As the pads wear, the caliper pistons extend further to compensate, leading to a decrease in the brake fluid level in the master cylinder reservoir.

Question 5

Which type of disc brake caliper may leak fluid more often?

Accepted Answer

The answer of Which type of disc brake caliper may...

Question 6

A quick take-up master cylinder is required when what type of caliper design is used on a vehicle?

Accepted Answer

Low-drag caliper designs require a quick take-up master cylinder to quickly compensate for the caliper's retraction from the rotor, ensuring prompt brake engagement.

Question 7

Technician A says that all vehicles equipped with rear disc brakes use a parking brake that is integrated in the caliper. Technician B says that all vehicles equipped with rear disc brakes use a small drum brake inside the rear rotor for a parking brake. Which technician is correct?

Accepted Answer

Vehicles with rear disc brakes may use different types of parking brake mechanisms. Some use a mechanism integrated into the caliper, while others use a small drum brake inside the rotor. Therefore, neither technician is correct in stating that all vehicles use one specific type.

Question 8

The brake pad edge code letters "FF" mean ________.

Accepted Answer

The brake pad edge code letters "FF" indicate the coefficient of friction rating. This rating helps to understand the friction characteristics of the brake pad material, which is crucial for braking performance.

Question 9

Semimetallic brake pads are made by a process called ________.

Accepted Answer

Semimetallic brake pads are made by sintering, a process that involves heating and pressing metal particles together without melting them, to create a durable material suitable for brake pads.

Question 10

Technician A says that riveted disc brake pads are often quieter that bonded disc brake pads. Technician B says that integrally molded disc brake pads are molded into holes in the steel backing of the pads. Which technician is correct?

Accepted Answer

Riveted disc brake pads can be quieter due to the way they are attached, reducing vibration. Integrally molded disc brake pads are indeed molded into holes in the steel backing, providing a secure attachment.

Question 11

Technician A says that brake fade due to lining or water is not possible on disc brakes. Technician B says that lining and water fade can occur on disc brakes, but is not as likely compared to drum brakes. Which technician is correct?

Accepted Answer

Technician B is correct because while disc brakes are less susceptible to fade caused by heat or moisture compared to drum brakes, they can still experience these issues under certain conditions.

Question 12

Technician A says that one disadvantage of disc brakes is noise. Technician B says that disc brakes are easier to equip with a parking brake mechanism than drum brakes. Which technician is correct?

Accepted Answer

Technician A is correct because disc brakes can indeed be noisier than drum brakes due to their design and operation. Technician B is incorrect because it is generally easier to integrate a parking brake mechanism with drum brakes than with disc brakes, as many vehicles use a small drum brake within the hub of the disc brake specifically for the parking brake.

Question 13

Technician A says that all slides and caliper bushings should be lubricated for proper operation. Technician B says that lubricant should not be used on disc brake parts because it can trap and hold dirt. Which technician is correct?

Accepted Answer

Technician A is correct because lubricating slides and caliper bushings is essential for proper brake operation, ensuring that the caliper can move freely. Lubricants designed for brake systems do not trap dirt when used correctly.

Question 14

Two technicians are discussing the construction of a single piston caliper. Technician A says that the fluid is retained by a piston seal fitted in a groove machined in the piston. Technician B says that the piston is held in the caliper by a lock ring. Which technician is correct?

Accepted Answer

In a single piston caliper, the fluid is retained by a piston seal fitted in a groove machined in the caliper bore, not the piston. The piston is not held by a lock ring; it is typically held in place by the caliper design and the hydraulic pressure.

Question 15

When the pressure in a caliper is released, the piston is moved back in the cylinder by ________.

Accepted Answer

The action of the piston seal is responsible for moving the piston back into the cylinder when the pressure in a caliper is released. The seal flexes out during application of the brakes, and when the pressure is released, it returns to its original shape, pulling the piston back with it.

Question 16

Disc brakes have many advantages, some of which are listed below. Which of the following statements does NOT apply to disc brakes?

Accepted Answer

Disc brakes are not self-energizing; this characteristic applies to drum brakes, where the design inherently multiplies the braking force.

Question 17

The outboard shoe of a single piston caliper is pushed against the rotor by the ________.

Accepted Answer

The answer of The outboard shoe of a single piston...

Question 18

Single-piston type disc brakes are adjusted by ________.

Accepted Answer

Piston movement through the seal adjusts single-piston type disc brakes. This occurs as the brake pads wear down, and the piston extends further out of the caliper to maintain the correct distance between the pad and the disc.

Question 19

Low-drag calipers maintain a closer running clearance between the rotor and brake pads than other types of calipers.

Accepted Answer

Low-drag calipers are designed to retract the brake pads slightly away from the rotor after braking to reduce residual drag, thus maintaining a slightly larger running clearance compared to other types of calipers.

Question 20

Which of the following is NOT a part of a brake caliper assembly?

Accepted Answer

The answer of Which of the following is NOT a...

Quiz 101: Disc Brakes