WITH CORRECT ANSWERS 2025-2026
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On a car with disc/drum brakes, the front brakes grab quickly when light pedal pressure is applied.
This problem could be caused by a bad:
A. proportioning valve
B. pressure safety switch
C. metering valve
D. residual check valve CORRECT ANSWER
C. The metering valve delays the flow of brake fluid to the front calipers until the pressure in the s
ystem rises to a point where the wheel cylinder can overcome the tension of the brake shoe retur
n springs. The purpose is to have both front and rear brakes apply simultane ously. This prevents t
he front brakesfrom locking up during light brake applications.
The driver of a vehicle with power disc/drum brakes says the brake pedal moves slowly to the floo
r while maintaining pedal pressure at a spotlight. What could cause this problem?
A.Leaking primary piston cup in master cylinder
B.Leaking power brake booster
C.Leaking residua check valve in master cylinder
D.Internal leak in the combination valve CORRECT ANSWER
A.If the primary piston cup in the master cylinder is leaking,pressure will not build up ahead of the
primary piston to increase pressure to the rear brakes. The piston will then move forward until th
e spring is compressed enough to move the secondary piston. Consequently, this internal leak will
cause the brake pedal to slowly drop to the floor.
What is the purpose of the master cylinder residual check valves on vehicles equipped with drum
brakes?
A.Allows the driver to pump up the brakes
B.Prevents air from entering the hydraulic system
C.Prevents wheel lockup by reducing the hydraulic pressure
D.Reduces pedal pulsation by controlling hydraulic pressure CORRECT ANSWER
B.Residual check valves are used on drum brakes to keep residual low pressure (slight static pressu
re) in the brake system at all times even when the brake pedal is released. This pressure (5-
, 20 psi) keeps the lips of the wheel cylinder piston cups tight against the cylinder walls to prevent
air from entering the system what at rest (brakes released).
A technician has just overhauled the front brakes on a vehicle with front disc and rear drum brake
s. However, when he attaches a pressure bleeder (pressurized to about 25psi) to the master cylind
er, he cannot get any fluid to come out of the disc brake caliper bleeder screws. Which of the foll
owing is MOST LIKELY the cause?
A. Bad proportioning valve
B. Bad pressure differential valve
C. Proportioning valve release button not activated
D. Metering valve release button not activated CORRECT ANSWER
D. A metering valve requires a minimum pressure (typically between 75-
125) to open. At this point pressurized fluid flows to the front calipers. Since the bleeder tank is o
nly pressurized to 25psi, fluid pressure is too low to open the metering valve during this procedure
. Therefore, when you use a pressure bleeder on a system with a metering valve you must manual
ly keep the valve open by either pushing the button in on the end of the valve, or pulling the ste
m outward on the end of the valve.
On a vehicle with single piston floating caliper front disc brakes, the brake pads on the left side of
the vehicle are almost completely worn while the right side is almost new. Technician A says that
too much rotor runout could be the cause. Technician B says that a binding caliper piston could be
the cause. Who is right?
A. Technician A only
B. Technician B only
C. Both A and B
D. Neither A or B CORRECT ANSWER
B. Excessive rotor runout would cause a pulsating brake pedal, but not even side to side pad wear.
A frozen caliper piston on the other hand, will keep both inner and outer brake pads equally appl
ied against the rotor even when the brake pedal is released. This constant friction will cause rapid
pad wear in the affected caliper as well as a front end pull.
A hydraulic brake line is leaking. Which of the following is the correct repair procedure?
A.Cut out the bad section and replace with new steel tubing using compressed fittings
B. Replace the leaking line with double flared, seamless copper tubing
C. Cut out the bad section and replace with single flared steel tubing using flare nuts and unions