Komatsu 930E-2, Shop Manual

Page: 494 / 739

Equipment Requirements
The following equipment will be necessary to properly
check-out the hydraulic steering circuit
•
Hydraulic schematic, refer to Section “R”.
•
Two 0-5000 psi (0-35,000 kPa) range cali-
brated pressure gauges and hoses.
•
A graduated container marked to measure liq-
uid volume in cubic inches or milliliters.
Pump Pressure Control Adjustments
With the brake system functioning properly and the
parking brake on, proceed as follows:
1. Place selector switch in NEUTRAL, apply the
parking brake and place the Rest switch in the
ON position and the GF Cutout Switch in the
CUTOUT position. Shut down engine and turn
key switch off. Wait 90 seconds for the steering
accumulators to completely bleed down before
opening circuits to take leakage measurements,
to make repairs, or to install or remove a gauge.
Be sure steering accumulator oil pressure has
been bled down. Turn the steering wheel; the
wheels should not move if all oil pressure has been
relieved.
2. Check hydraulic oil level in tank and add oil if
required. Be certain suction line shut-off valves
are open.
3. Remove plug and install an accurate 5000 psi
(35,000 kPa) pressure gauge at the steering
pressure “GPA” test port (4, Figure 10-1) located
on the suction side of the pump. Install a second
5000 psi (35,000 kPa) gauge in the bleeddown
manifold test port “TP2” (3, Figure 10-2).
4. Turn unloader valve adjustment screw (2, Figure
10-1) clockwise until it bottoms out.
5. Back out the pressure compensator adjustment
screw (3), by turning counterclockwise.
FIGURE 10-1. PUMP PRESSURE CONTROLS
1. Stroke Adjustment
2. Unloader Adjustment 3. Compensator Adjustment
4. GPA Port
FIGURE 10-2. BLEEDDOWN MANIFOLD
1. To Hoist Valve, Power Up
2. To Hoist Valve, Power Down
3. Pressure Test Port (TP2)
4. To Brake System
5. Steering System Pressure Switch
6. Accumulator Bleeddown Solenoid
7. Pressure Test Port (TP3)
8. Supply To Flow Amp
9. Return From Flow Amp
10. To Front Steering Accumulator
11. To Rear Steering Accumulator
12. Relief Valve, 600 psi (4.1 MPa)
13. Relief Valve, 4000 psi (28.0 MPa)
14. Hoist Pilot Valve Return
15. Return to Tank
16. Feedback Pressure to Unloader valve
17. Supply From Pump
L10-2 Hydraulic Check-out Procedure L10012