Jacobsen SLF 1880, Technical/Repair Manual

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8N-94
Figure 8N-1. In-Line Flow Tester
PRESSURE TESTS
The pressure tests are frequently inconclusive in isolat-
ing a faulty component. A flow test is recommended for
isolating a problem within a circuit. The pressure tests
are useful in determining the pressure settings of pres-
sure relief valves.
STEERING CIRCUIT PRESSURE
TEST
1. Shut off the engine.
2. Install a 2000-psi (138 Bar) pressure gauge and
in-line tee between the steering unit inlet and the
supply hose (Figure 8N-2).
3. Set the parking brake, start engine, and advance
engine speed to full throttle position.
4. Turn the steering wheel to the full left or right posi-
tion and observe the pressure gauge.
5. Record the pressure gauge reading. The steering
relief pressure should be 1160-psi (80 Bar) +/-
10% (Figure 8N-2).
Conclusion
• If relief valve opens within range, relief and steering
are not at fault.
• If relief pressure is not within range, relief valve and
charge pump should be checked.
6. Shut off the engine and remove the ignition key.
Steering Relief Valve
7. Remove steering system relief valve plug, spring,
and cone. Inspect for sediment or debris and dam-
age. Clean or replace as necessary.
• If the relief valve is not clogged or damaged:
8. Remove the hydraulic lines from the steering cyl-
inder. Cap the cylinder ports and plug the hydrau-
lic hoses.
9. Set the parking brake, start engine, and advance
engine speed to full throttle.
10.Slowly turn the steering wheel to the full left and
right position and observe the pressure gauge.
11. Record the pressure gauge reading. The steering
relief pressure should be 1160-psi (80 Bar) +/-
10% (Figure 8N-2).
Conclusion
• If pressure is within range, the steering cylinder is at
fault. Repair or replace steering cylinder
(Section 6D).
• If pressure is not within range, the steering unit or
charge pump is at fault. Proceed with charge pump
flow test (Section 8G).
NOTICE
The instrument tests described in this section are
intended as a guide only and may not include every
problem encountered within a hydraulic system Con-
tact your local Jacobsen dealer for additional infor-
mation and assistance.
NOTICE
Perform the Charge Pump Test before performing
the steering circuit test (Section 8G).
Load
Valve
IN OUT
NOTICE
The steering relief valve cannot be repaired or
adjusted. Replace if damaged or faulty (Figure 8N-
2).