Chapter 109 Power Brake Unit Operation, Diagnosis, and Service
Quiz by Matt Lobdell
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- Q1
A power brake booster provides which of the followingdesign features?
Reduced stopping distance
High brake pedal effort
Reduced pedal effort
A lower brake pedal position
30s - Q2
The proper operation of a vacuum brake booster requires that the engine be capable of supplying at least ________.
21 in. Hg vacuum
15 in. Hg vacuum
17 in. Hg vacuum
19 in. Hg vacuum
30s - Q3
A defective vacuum brake booster will cause a________.
hard brake pedal
low brake pedal
soft (spongy) brake pedal
slight hiss noise when the brake pedal is depressed
30s - Q4
A brake pedal feels spongy when depressed. Technician A says that a defective hydraulic brake booster could be the cause. Technician B says that a defective vacuum brake booster could be the cause. Which technician is correct?
Technician A only
Technician B only
Both technicians
Neither technician
30s - Q5
Two technicians are discussing vacuum brake boosters. Technician A says that a low, soft brake pedal is an indication of a defective booster. Technician B says that there should be at least two power-assisted brake applications after the engine stops running. Which technician is correct?
Technician A only
Technician B only
Both technicians
Neither technician
30s - Q6
Technician A says that to check the operation of a vacuum brake booster, the brake pedal should be depressed until the assist is depleted and then start the engine. Technician B says that the brake pedal should drop when the engine starts, if the booster is okay. Which technician iscorrect?
Technician A only
Technician B only
Both technicians
Neither technician
30s - Q7
Which of these could be caused by an improperly adjusted booster pushrod?
A soft pedal
Brakes to overheat
A low pedal
None of these
30s - Q8
An accumulator, such as that used on hydraulic brake boosters________.
provides higher force being fed back to the driver'sfoot
provides a reserve in the event of a failure
reduces brake pedal noise
works against engine vacuum
30s - Q9
The first step in diagnosing a Hydro-Boost problem is________.
a thorough visual inspection
to tighten the power steering drive belt
a pressure test of the pump
a volume test of the pump
30s - Q10
If the engine stops running, what is the most likely to occur if the vehicle is equipped with a Hydro-Boost power brake system?
A low and spongy brake pedal
A high and hard brake pedal
Greatly reduced braking distance but a normal feeling brake pedal
Normal braking using the accumulator pressure
30s - Q11
Two technicians are discussing vacuum brake boosters. Technician A says that when the engine is running and the driver's foot is off the brake pedal, a vacuum is present on both sides of the booster diaphragm. Technician B says that when the brakes are in the applied position, vacuum is present on the front side of the diaphragm. Which technician is correct?
Technician A only
Technician B only
Both technicians
Neither technician
30s - Q12
To provide the driver with a sense of "feel"during braking, vacuum boosters use a ________.
return spring
pressure restrictor
diaphragm spacer
vacuum diverter
30s - Q13
A hydraulically operated booster unit stores fluid under pressure by means of a(n) ________.
accumulator
actuator
pressure chamber
boost piston
30s - Q14
A common source of vacuum for boosters used on diesel engines is ________.
exhaust manifold
carburetor
auxiliary vacuum pump
intake manifold
30s - Q15
Technician A says when the brakes are applied in a vacuum booster, the vacuum control valve is closed. Technician B says the vacuum control valve is opened. Which technician is correct?
Technician A only
Technician B only
Both technicians
Neither technician
30s