Technician A says that any imperfection found in a phenolic caliper piston warrants replacement. Technician B says that a phenolic caliper piston should be protected with a block of wood when installing it into the calip
...
Technician A says that any imperfection found in a phenolic caliper piston warrants replacement. Technician B says that a phenolic caliper piston should be protected with a block of wood when installing it into the caliper bore with a C-clamp. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B
(> - The correct answer is B. A phenolic piston should be protected to keep it from being damaged when a C-clamp is used. Technician A is wrong because minor surface imperfections are OK provided they do not enter the dust boot groove area.
Which of the following should be used to measure the thickness of a scored rotor?
A. Vernier caliper
B. Outside micrometer with flat anvil and spindle
C. Inside micrometer
D. Outside micrometer with pointed anvil and spindle
(> - The correct answer is D. AN outside micrometer with a pointed anvil and spindle is a disc brake micrometer. unlike a standard micrometer that uses a flat surface on the anvil and spindle, a disc brake micrometer uses pointed tips so the instrument can fit into the groves of scored rotors, to accurately measure the thickness.
During a routine vehicle maintenance, the fluid level in the master cylinder reservoir is checked. When the reservoir cap is removed, purple colored fluid is found in the reservoir. Technician A says that this means the fluid should be topped off with DOT 4, which has a higher boiling point than regular brake fluid. Technician B says that this means that the fluid is contaminated; all rubber parts in the system must be replaced and the system flushed. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B
(> - The correct answer is D, neither technician is right. Purple is the color of silicone fluid, and only DOT 5 fluid should be used to top off the reservoir.
A complete front brake service has just been performed on a vehicle with disc brakes: rotora turned, calipers rebuilt, new brake pads, bearings repacked and adjusted. However, when the vehicle is road tested, a pulsation can be felt through the pedal. Which of the following is the MOST LIKELY cause of the pulsation?
A. Non-directional finish not applied to rotors
B. Wrong lining compound chosen
C. Over-torqued lug nuts
D. Incorrect bleeding sequence
(> - The correct answer is C. Over-tightening the lug nuts can distort the rotor and create excessive runout, resulting in a pedal pulsation. All of the other choices may cause other problems, but not a pedal pulsation.
Brake fluid leaking from a cracked brake line causes the brake light on the dashboard to come on in response to the loss of hydraulic pressure. Which of the following valves in the hydraulic system switched on the light?
A. metering valve
B. pressure differential valve
C. proportioning valve
D. residual check valve
(> - The correct answer is B. The pressure differential valve and warning switch alerts the driver of a pressure loss in one of the hydraulic circuits. The residual check valve is often used in the master cylinder outlet port of a drum brake systems in order to maintain a slight pressure in the brake lines and wheel cylinders, which keep wheel cylinder piston tight against their bores. the metering valve delays front disc brake operation until the rear brakes shoes overcome the return spring tension. The proportioning valve is used to control rear brake pressers, particularly during hard stops.
Technician A says that an integral ABS system is an add-on system. Technician B says that a non-integral ABS system is high-pressure system. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B
(> - The correct answer is D, neither technician is right. The non-integral ABS system is added on the vehicle's existing hydraulic brake systen, and is generally a low-pressure arrangement.
[Show More]
