7 Steering System

7 Steering System 7.1 Checking the Steering System

Prerequisites 200-bar (3000-psi) pressure gauge

Background A badly worn exciter pump will affect both the steering and the vibration circuits because these circuits operate in series using the same supply. If hydraulic pressure to both circuits falls below operating pressures, replace the exciter pump. Note: In some cases the exciter pump may function well enough to operate the steering circuit but not the vibration circuit. This is due to the much lower pressure requirements of the steering circuit.

Procedure Follow the procedure below to check the steering system. 1.Open the engine compartment. 2.Locate the exciter solenoid valve (a).

3.Connect a 200-bar (3000-psi) gauge to the test port (b). 4.Start the engine. 5.Check the pressure while operating the steering. NOTICE: Do not turn on the vibration while conducting this test. The 3000-psi gauge will be damaged. Normal operating pressure: 55–69 bar (800–1000 psi) Pressure while turning: 90–117 bar (1300–1700 psi)

The steering system has now been checked.

If Then

The pressure is near zero, The cooling fan is bound; replace it.

The pressure is low, Check pressure in vibration circuit. See section Troubleshooting a System that Vibrates Poorly. If the vibration circuit pressure is low, replace the vibration pump.

The pressure is high (over 138 bar (2000 psi)), Check the steering cylinder for binding and replace it if necessary. If the steering cylinder is OK, replace the steering valve.