Komatsu 830E-AC Shop Manual page 773

Steering Pump Leakage Check
To check for worn piston pump, measurement of the
leakage can be made from the case drain while the
pump is under pressure.
1. Disconnect steering pump drain line from the
hydraulic tank and securely plug port in hydrau-
lic tank with a steel cap.
2. Connect a flow meter to the pump drain line or
have the drain line directed into a large con-
tainer or reservoir. The pump case must remain
full of oil during this test.
3. Connect a calibrated 35,000 kPa (5000 psi)
pressure gauge to diagnostic receptacle located
on the junction block from the outlet hose from
the steering pump.
4. Start engine and warm hydraulic oil to operating
temperature of 43°C (110°F).
5. With engine at 1800 rpm and accumulator com-
pletely full, verify steering pressure is 22,064
kPa (3200 psi) on pressure gauge. Adjust
unloader valve pressure if necessary.
6. Read the flow meter or time the case drain flow
used to fill a known size container and calculate
the flow rate in terms of cubic inches per minute
3
(in. /min.).
7. The leakage should not exceed 5.25 liters per
minute (177 oz. per min.) at 22,064 kPa (3200
psi) system pressure. Additional leakage indi-
cates wear, but does not become critical until it
impairs performance.
BLEEDDOWN MANIFOLD
Adjustment of the relief valves is not necessary or
recommended. Relief valves are factory preset. Do
not attempt to rebuild or repair if relief valves are
defective. Replace as a unit. The steering pressure
switch and check valves are also replaced only as
units.
L10028
SHOCK & SUCTION VALVES
Shock & Suction Valve Settings
Relieve pressure before disconnecting hydraulic
lines. Tighten all connections securely before
applying 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 type of injury is not
received immediately.
Be sure accumulator oil pressure has been bled
down. Turn steering wheel; the wheels should
not move if oil pressure has been relieved.
1. Shut down engine, turn key switch OFF and
allow accumulator to completely bleed down
before opening circuits to take measurements,
to make repairs, or to install or remove gauges.
2. Install a calibrated 35,000 kPa (5000 psi) gauge
on one of the two diagnostic ports located on
the steering cylinder manifold located just below
the engine.
3. Prior to checking the shock & suction valves in
the flow amplifier, raise the steering relief pres-
sure.
a. Remove steering relief valve external plug
Hydraulic Check-out Procedure
using an 8 mm metric allen wrench. Refer to
Figure 10-3.
L10-5