Section I. GENERAL
(Sheet 1 of 2)
pedal is released the oil pressure at each wheel is released and the oil
1. HYDRAULIC OIL TANK. The storage reservoir for all of the hydraulic oil
is returned to the oil tank.
used in the machine except for the transmission and torque converter.
TRANSMISSION NEUTRALIZER CONTROL VALVE. Controls hydraulic
An inlet strainer provides filtering when adding or replacing oil to the
oil pressure which disengages the transmission as the left brake pedal is
tank. Also, a filter is built into the tank for filtering all of the oil returning
depressed. This provides full engine power to the hydraulic systems as
from the hydraulic system. Oil is pumped from the tank through the
the vehicle is braking or stopped. The valve is designed so when the
braking components and re- turned back to the tank.
brake pedal is released the transmission engages slightly before the
2. HYDRAULIC OIL LINES. Serve as passages for the pressurized oil to
brakes are released.
operate the different braking components.
SERVICE BRAKES. Oil pressure activated disc-type brakes are at all
3. HYDRAULIC PUMP. The hydraulic pump serves two systems, steering
four wheels. Operating in the final drive housing oil keeps them cool. As
and braking. It is a positive displacement gear type pump driven by the
a brake pedal is applied it allows pressurized oil from the brake control
engine. The smaller section of the pump supplies high pressure oil to
valve to push a piston against a set of plates and discs. The discs rotate
operate the brake system. Oil is pumped from the hydraulic tank to the
with the wheel and the plates are stationary. Friction between the plates
accumulator charging valve and distributed to the system.
and discs slows or stops the turning wheel. Releasing the brake pedal
4. ACCUMULATOR CHARGING VALVE. Distributes flow of oil, from
allows the pressurized oil to return to the oil tank. The friction between
pump, to brake and hydraulic oil cooler control systems. Contains a
the plates and discs is eliminated and the wheels are permitted to turn
check valve and a pressure relief valve. Check valve keeps pressure in
accumulator in a constant range of 1950 PSI (137.1 kg/cm2) maximum
EMERGENCY AND PARKING BRAKE. Located on the transfer gear
to 1450 PSI (101.9 kg/cm2) mini- mum. Pressure relief valve controls
case housing. A disc-type brake with stationary plates and rotating discs.
maximum oil pressure in accumulator if accumulator charging valve
Spring pressure applies the brake which stops the transfer gear shaft.
The brake is released by oil pressure from the accumulator tank.
5. ACCUMULATOR. Located below the left hand service door. It has a
sealed piston which divides the accumulator into two chambers. The
If, due to a malfunction in accumulator charging circuit, pressure drops
upper chamber contains dry nitrogen gas. Pumping oil into the lower
below 700 PSI (49.2 kg/cm2), the emergency brake will automatically
chamber moves the piston up compressing the gas. The charging valve
limits the gas compression to 1950 PSI. Pushing either brake pedal
EMERGENCY AND PARKING BRAKE CONTROL VALVE. Controls oil
releases the oil under pressure and allows it to activate the brake control
flow to the emergency and parking brake. Valve is normally activated by
the operator. Pulling out on the parking brake control knob releases oil
6. BRAKE CONTROL VALVE. Controls the amount of high pressure oil
pressure and activates the brake. Pushing the knob in hydraulically
from the accumulator to the wheel brakes. Changing the position of
releases the brake by removing the spring tension holding the plates and
either pedal will increase or decrease the oil pressure at the wheel. As a
discs together. The parking brake control is on the right side of the
brake pedal is applied, oil pressure at each wheel brake is increased,
slowing or stopping the wheel. As the
Go on to Sheet 2