Figure 34-27. Bellows-Type Booster.
as the bellows type. The power assist unit, however, Is of
the sliding piston or diaphragm type.
34-37. Hydraulic-Power Booster. The hydraulic-power
called a hydroboost
operated by hydraulic pressure developed by the power
steering pump. Should the power steering pump become
Inoperative, an auxiliary electric pump then is used for
backup and safety reasons. The hydraulic booster Is
attached directly to the master cylinder and is actuated
by the brake pedal. The hydroboost system has an
accumulator built into the system The accumulator,
which is spring loaded and can also contain pressurized
gas, is filled with fluid, and pressurized whenever the
brakes are applied. Should the power steering system
fail because of a lack of fluid or a broken belt, the
accumulator will retain enough fluid and pressure for
about three brake applications.
Figure 34-28. Brake Pedal Booster.