TM 5-3805-262-20
1-26. BRAKES (CONT)
PRESSURE PROTECTION VALVE. Performs two functions:
(1) permits fast increase in
pressure in air reservoir when pressure in system is below 65 psi and (2) keeps
pressure in air reservoir if an air leak in hydraulic reservoir or between pressure
protection valve and hydraulic reservoir exists . Pressure protection valve opens
when pressure in air reservoir increases to approximately 85 psi and closes when
pressure decreases to approximately 65 psi.
PRESSURE REDUCING VALVE. Mounted in hydraulic reservoir air pressure line. Decreases
air pressure applied to hydraulic reservoir to 7 to 12 psi.
Air pressure is applied
to the hydraulic reservoir to ensure a constant oil supply when loader is traversing
up or down a steep incline and to prevent cavitation of hydraulic oil.
RELIEF VALVE.
Mounted in pressure reducing valve port. P r o t e c t s h y d r a u l i c r e s e r v o ir
from excessive air pressure. Vents air when pressure exceeds 12 psi.
AIR HORN AND HORN VALVE.
Air horn activated by pressure on horn valve button locat-
ed on cab deck near inching treadle. Depressing horn valve button applies air pres-
sure to horn causing horn diaphragm to vibrate and sound.
PARKING BRAKE VALVE AND ACTUATOR.
Pushing in knob of parking brake valve routes air
pressure to parking brake actuator. This air pressure pushes against piston and
spring in parking brake actuator. As piston moves, linkage connected between
actuator and parking brake assembly releases parking brake and permits normal use of
l o a d e r. A minimum of 60 psi air pressure is necessary to hold parking brake in re-
leased position. Pulling out knob of parking brake valve releases air from parking
brake actuator through parking brake valve .
Spring in parking brake actuator then
applies parking brake assembly. Loader cannot be moved until knob of parking brake
valve is pushed in or parking brake assembly is manually released.
PRESSURE SWITCH.
Mounted in parking brake valve port. Switch is closed when air
pressure not applied to parking brake actuator. This turns brake indicator located
on instrument panel cluster on. When air pressure applied releasing parking brake
actuator, switch opens, turning brake indicator off.
WARNING BUZZER SWITCH.
Mounted in parking brake valve port. Closes to sound warning
buzzer when air pressure in system is less than approximately 70 psi. Warning buzzer
mounted on right instrument panel.
WASHER CONTROL AND FLUID RESERVOIR.
Control mounted on left instrument panel; fluid
reservoir mounted in hydraulic reservoir area, right side. Pressing washer control
applies pressure to fluid reservoir forcing water through hose and nozzle mounted in
front of windshield.
1-27. STEERING SYSTEM
See figure FO-11
STEERING GEAR.
Steering is controlled by steering wheel in cab. Steering wheel me-
chanically connected to steering gear. Position of steering wheel varies oil flow
through steering gear which in turn varies flow of oil to steering cylinders con-
t r o l l i n g d i r e c t i o n o f l o a d e r.
1-26
