ASE T4 Practice Test

A truck with air brakes has a pedal that feels spongy and goes to the floor when applied. The most likely cause is:

What is the typical cause of a rapid brake chamber stroke increase when a brake application is made?

During an inspection, a technician observes oil in the air brake system. This is most likely due to:

During a high-pressure test, the air pressure drops significantly after the engine is turned off. The FIRST component to suspect would be the:

When a service brake application feels uneven or jerky, what should be suspected?

A continuous air leak from the tractor protection valve exhaust with the trailer connected and the system pressurized indicates:

A technician notices that an air brake-equipped vehicle takes longer than usual to stop. The first component to inspect should be the:

When a heavy-duty truck is experiencing low braking power, and there are no air leaks or mechanical faults, the next component to inspect should be the:

When a manual slack adjuster has more than one inch of free play at the pushrod, what is the likely cause?

After an air tank drain, the low pressure warning signal activates too late as pressure falls. The most probable cause is:

When testing a tractor with a fully charged air system, the trailer brakes do not release. What should be checked first?

What would likely cause a decrease in air pressure after a foot valve rebuild during the foot valve leak test?

What is the MOST likely cause of a spring brake chamber not releasing on a tandem axle truck?

During a routine inspection, a technician finds that the air compressor's discharge line is extremely hot. This condition could be caused by:

If the air brake system has a significant delay in pressure drop after the engine is shut off, what is the most likely problem?

A technician notes that the air brake compressor cycles more frequently than normal. The FIRST thing to inspect would be:

The air pressure gauge shows a slower build-up of air pressure than normal. What could be the cause of this condition?

During a road test, a truck's air brake system activates the ABS intermittently under normal braking conditions. The most likely cause is:

If an automatic slack adjuster must be manually adjusted often, what is the probable cause?

A heavy-duty truck experiences uneven braking action. The most likely cause could be:

After replacing an S-Cam on a drum brake system, the technician notices a squealing noise during brake application. The first step in troubleshooting should be:

After replacing the brake shoes on a truck with S-cam brakes, the technician notices that one wheel requires more air pressure to apply the brake than the others. What is the MOST likely cause?

An air brake system has a new compressor but still struggles to build up pressure. What should be checked first?

In a dual circuit air brake system, when one circuit fails to maintain pressure, what should be checked first?

The spring brakes release when air pressure is removed from the parking brake circuit. What is the probable cause?

During the initial pressure build-up from 85 to 100 psi, the air pressure rises too slowly. What component should be inspected?

A truck with S-cam drum brakes has uneven brake shoe wear. The LEAST likely cause of this would be:

A driver reports that the air pressure warning buzzer activates at normal pressures. The most likely cause is:

During a full-function valve test, a slow return to normal cut-out pressure after the valve is released suggests:

A technician finds that the air brake system does not release immediately after the air pressure builds to a normal range. The probable cause is:

During a brake application, air pressure does not build up in the secondary circuit of a dual air system. What should be the primary area of focus for diagnosis?

When testing a truck with air brakes, a technician notices that the spring brakes do not apply automatically when the system air pressure drops below a certain level. The FIRST component to inspect should be:

A heavy-duty truck experiences uneven braking action. The most likely cause could be:

When diagnosing a hydraulic brake system, the technician notes that the brake pedal feels spongy even after bleeding the system. The most likely cause is:

A truck's brake pedal goes to the floor and the brake warning light is on. However, there are no visible leaks and the master cylinder reservoir is full. The FIRST step to diagnose this issue should be:

A technician is diagnosing a hydraulic brake system and finds that one front wheel is not braking effectively. The most likely cause is:

During a brake system inspection, a technician finds that the front brake hoses are bulging under pressure. This is indicative of:

A heavy-duty truck experiences reduced braking efficiency and a hissing noise is heard when the brake pedal is depressed. The most probable cause is:

A vehicle with hydraulic brakes shows a tendency for one front wheel to lock up before the others during hard braking. The most likely cause is:

When inspecting a hydraulic brake system, a technician notes that the brake fluid appears milky and opaque. This is MOST likely due to:

A technician finds that a hydraulic brake system is losing fluid but no external leaks are visible. The most likely cause of this is:

After replacing the rear brake lines on a truck, the technician notices that the rear brakes lock up during light braking. The most likely cause is:

In a hydraulic brake system, a technician finds that the ABS light turns on intermittently. The MOST likely cause of this issue is:

After changing the brake pads on a truck, the technician notices that the pedal travel is excessive before the brakes engage. The FIRST thing to check should be:

During a brake system inspection, a technician finds that the front brake hoses are bulging under pressure. This is indicative of:

In a vehicle with a properly functioning ABS, heavy braking on a slippery surface will result in:

A heavy-duty truck with an ABS system displays uneven brake wear. The first component to inspect would be:

A fault code in an ABS system indicating an "open circuit" most likely pertains to:

When testing an ABS system, a technician notes that the ABS activates during normal braking conditions. This could be caused by:

What symptom indicates a potential failure in the ABS hydraulic control unit?