Component Description - Komatsu 830E Shop Manual

When servicing the hydraulic system, relieve
pressure before disconnecting hydraulic and
other lines. Tighten all connections before apply-
ing pressure.
Hydraulic fluid escaping under pressure can
have sufficient force to enter a person's body by
penetrating the skin and cause serious injury and
possibly death if proper medical treatment by a
physician familiar with this injury is not received
immediately.

COMPONENT DESCRIPTION

HOIST PUMP
The hoist pump (5, Figure 2-2) is a tandem gear type
pump. The pump is mounted behind the main alter-
nator and driven by a drive shaft connection between
the pump and the accessory drive output of the alter-
nator. The pump has a total output of 230 GPM (870
l/min.) at 1900 RPM.
STEERING/BRAKE PUMP
The Steering/Brake system pump (3) is mounted on
the rear of the hoist system pump and coupled to the
hoist pump driveshaft. This pump has an output of 65
GPM (246 l/min) at 1900 RPM. Output from this
pump provides oil for the truck steering system as
well as the service brake system.
TANK
The hydraulic tank provides a common supply of oil
for the hoist, steering, and brake systems. The
hydraulic tank service capacity is 238 Gal (901 l).
Oil leaving the hydraulic tank (1) passes through two
100 mesh wire strainers before entering the hydrau-
lic pumps. Oil level should be checked periodically
and be visible in the bottom sight glass when the
body is down and the engine is running. If filling is
required, use only clean, filtered type C-4 hydraulic
oil.
HIGH PRESSURE HYDRAULIC FILTERS
The truck is equipped with high pressure hydraulic oil
filters to filter the oil supply at the outlet of the pumps.
The steering/brake system filter (4) and two hoist cir-
L2-2
cuit filters (4, Figure 2-1) are located on the right
side, behind the fuel tank.
Flow restriction through the filter element is sensed
by a pressure differential switch. When restriction is
excessive, the switch will turn on an indicator lamp
inside the cab to notify the operator that filter service
is required.
BLEEDDOWN MANIFOLD
The bleeddown manifold (6, Figure 2-2) receives oil
from the steering/brake pump and directs it to the
steering accumulators (9), brake system, and to the
flow amplifier (7), for steering circuit components.
STEERING SYSTEM ACCUMULATORS
The steering accumulators (9) provide an adequate
volume of pressurized oil to allow the truck to be
steered to a safe area if a malfunction occurs in the
pump. (Brake system accumulators store a supply of
oil to allow several brake applications if the steering/
brake pump malfunctions. Refer to Section "J" for
detailed information.)
DISABLED TRUCK CONNECTORS
Quick disconnect fittings are provided to allow opera-
tion of the steering and brake circuits for temporary
truck operation if the steering/brake pump is not
operational. The steering circuit fittings (10) are con-
nected to another (operational) truck by hoses. A
jumper hose must be installed between the two brake
circuit quick disconnects (11) to enable service brake
operation. This will allow maintenance personnel to
move the truck to a suitable area for performing
repairs.
Another pair of quick disconnect fittings are installed
on the Overcenter Valve Manifold located above the
steering/brake pump. These fittings are used to
attach hoses to an operational truck in the event that
the hoist pump, hoist valve or other hoist system
component malfunctions. This will allow maintenance
personnel to raise the truck body to dump the load
before moving the disabled truck.
The steering circuit and hoist circuit relief valves are
adjusted to 2500 psi (17 240 kPa). The brake system
relief is adjusted to 3500 psi (24 132 kPa).
Refer to the appropriate information in this section of
the manual for repair and troubleshooting procedures
for the hoist system components and steering sys-
tem components. Refer to Section "J" for repair and
troubleshooting procedures for the hydraulic brake
system components.
Hydraulic System L02027