freeasestudyguides Brakes 16-20

After replacing the front brake calipers on a vehicle with a four-wheel disc brake system, the vehicle returns with brake drag. Which of the following is causing this condition?

• A twisted brake hose.

• Glazed brake shoes.

• Brake shoe adjustment.

• Glazed brake pads.

Answer explanation

A twisted brake hose can restrict fluid flow, causing brake drag. This issue is more likely than glazed pads or shoes, which typically cause noise or reduced performance rather than drag.

A lateral runout test is performed on all four rotors. Which of the following is correct about this test?

• This test checks for rotor thickness.

• This test checks for rotor parallelism.

• Use an outside micrometer.

• Use a dial indicator.

Answer explanation

The lateral runout test measures the variation in the rotor's surface as it rotates, which is best assessed using a dial indicator. This tool provides precise measurements of any deviations, unlike a micrometer.

The reading on the metric micrometer above indicates:

• 13.0 mm

• 14.5 mm

• 14.0 mm

• 13.5 mm

Answer explanation

The micrometer reading shows 14.5 mm, as indicated by the main scale and the thimble scale alignment. This is the correct measurement, confirming that 14.5 mm is the accurate choice.

Which brake line is best suited for automotive brake line replacement?

• Double-walled tin tubing.

• Double-walled steel tubing.

• Single-walled welded copper.

• Single-walled seamless copper.

Answer explanation

Double-walled steel tubing is the best choice for automotive brake line replacement due to its strength, durability, and resistance to corrosion, ensuring safe and reliable braking performance.

Technician A says a three-function combination valve contains the proportioning valve. Technician B says a three-function combination valve contains the metering valve. Who is correct?

• Both A and B

• Neither A or B

• Technician B

• Technician A

Answer explanation

Both technicians are correct. A three-function combination valve includes both the proportioning valve and the metering valve, serving multiple functions in the braking system.

What is the primary function of a proportioning valve in a brake system?

• To increase brake fluid pressure.

• To reduce brake noise.

• To prevent brake fluid leakage.

• To balance brake pressure between front and rear brakes.

Answer explanation

The primary function of a proportioning valve is to balance brake pressure between front and rear brakes, ensuring optimal braking performance and stability during braking.

What tool is used to measure rotor thickness?

• Outside micrometer

• Caliper gauge

• Torque wrench

• Dial indicator

Answer explanation

An outside micrometer is specifically designed to measure small dimensions like rotor thickness with high precision, making it the correct tool for this task. Other options do not provide the same level of accuracy.

What is the consequence of using a single-walled copper brake line?

• Enhanced flexibility

• Better corrosion resistance

• Increased risk of brake line failure

• Improved braking performance

Answer explanation

Using a single-walled copper brake line increases the risk of brake line failure due to its susceptibility to corrosion and pressure-related issues, compromising safety and performance.

What is the purpose of a metering valve in a brake system?

• To prevent brake fluid contamination

• To increase rear brake pressure

• To delay front brake application

• To reduce brake pedal effort

Answer explanation

The metering valve's purpose is to delay front brake application, allowing the rear brakes to engage first. This helps maintain vehicle stability during braking, especially in situations where weight transfer occurs.

Which component is not part of a three-function combination valve?

• Metering valve

• Brake failure light switch

• Proportioning valve

• Master cylinder

Answer explanation

The master cylinder is not part of a three-function combination valve. The three functions typically include a metering valve, proportioning valve, and brake failure light switch, while the master cylinder is a separate component.