Braking - Chevrolet 2009 HHR Owner's Manual

Braking

See Brake System Warning Light on page 3-33.
Braking action involves perception time and reaction
time. Deciding to push the brake pedal is perception
time. Actually doing it is reaction time.
Average reaction time is about three-fourths of a second.
But that is only an average. It might be less with one
driver and as long as two or three seconds or more with
another. Age, physical condition, alertness, coordination,
and eyesight all play a part. So do alcohol, drugs, and
frustration. But even in three-fourths of a second, a
vehicle moving at 60 mph (100 km/h) travels 66 feet
(20 m). That could be a lot of distance in an emergency,
so keeping enough space between the vehicle and others
is important.
And, of course, actual stopping distances vary greatly
with the surface of the road, whether it is pavement or
gravel; the condition of the road, whether it is wet, dry, or
icy; tire tread; the condition of the brakes; the weight of
the vehicle; and the amount of brake force applied.
Avoid needless heavy braking. Some people drive
in spurts — heavy acceleration followed by heavy
braking — rather than keeping pace with traffic.
This is a mistake.
4-4
The brakes might not have time to cool between hard
stops. The brakes will wear out much faster with a lot
of heavy braking. Keeping pace with the traffic and
allowing realistic following distances eliminates a lot of
unnecessary braking. That means better braking and
longer brake life.
If the engine ever stops while the vehicle is being driven,
brake normally but do not pump the brakes. If the brakes
are pumped, the pedal could get harder to push down.
If the engine stops, there will still be some power brake
assist but it will be used when the brake is applied. Once
the power assist is used up, it can take longer to stop and
the brake pedal will be harder to push.
If the vehicle has Electronic Stability Control (ESC) and
the 2.0L turbocharged engine, it also has a hydraulic
brake boost feature which supplements the power brake
system to maintain consistent brake performance under
conditions of low brake booster vacuum. Low brake
booster vacuum conditions can include initial start up
after the vehicle has been parked for several hours, very
frequent brake stops, or high altitude driving. When
hydraulic brake boost is active, minor brake pulsation or
movement might be felt but this is normal. If brake pedal
feel changes or the brake pedal feels hard to push, the
system might not be receiving the intended brake boost
and the SVC BRAKE SYSTEM DIC message may be
displayed.