What does the parking brake do?
In road vehicles, the parking brake is used to keep the vehicle stationary and, in many cases,
also perform an emergency stop. Parking brakes on older cars often consisted of a cable connected to the rear brakes and the other end to a pulling
mechanism which is operated with the
driver's hand or foot. The mechanism may
be a hand-operated lever, at floor level beside the driver, or a straight pull
handle located near the steering column
or a (foot-operated) pedal located beside
the driver's leg. Some automobiles
have the parking brake operate on the
front wheels, for example, most Citroens
manufactured since the end of World War II, and the early models of the Saab
900.
The most common use for a parking brake is to keep a vehicle
motionless when it is parked. The parking
brake has a ratchet or other locking mechanism that will keep it engaged until
manually released. On cars with automatic
transmissions, this is usually used in
concert with a parking pawl in the transmission.
When Should you
use the parking brake?
On both manual transmissions and automatic transmissions, it
is a good idea to use the parking brake whenever
you are parking on uneven ground.
Manual transmissions have some play in the gearing that allows some play. It is possible with enough force to move a
vehicle even if it is in gear.
Automatic
transmissions have what’s called a
parking pawl that prevents the transmission from moving when in park.
The parking pawl can break if enough force is applied to it.
Another reason to use the parking brake when parking on
hilly terrain is the gears inside the
transmission can get jammed by the car rolling a slight amount after releasing the
brake. That can make it hard to get out
of gear.
By using the parking brake, you
are preventing the car from rolling.
When should you
not use the
parking brake?
There is no need to use the parking brake when parking on level ground. You should also not use the parking brake in
winter. During winter if any moisture
gets on the cable such as snow, slush or
water then it can freeze causing the parking brake to stick. If the parking brake sticks on, then the
back tires will not spin while trying to move.