Turn steering up to lock and pull for a short moment (max. 5 s) at 200 N on steering wheel, so that
the steering valve is completely closed. Repeat test in opposite turning direction.
for steering circuit II 2.5 dm3/min at 100 bar
for steering circuit I 2.5 dm3/min at 100 bar
If these values are exceeded, the cause may be an excessive oil leak in steering or in power
Steering System Without Power Cylinder
Unscrew line from steering to power cylinder, which is under pressure when the steering wheel is
turned clockwise and close connection to steering with a plug. Repeat leak oil test as described
under Para. 22.214.171.124, Steering System with Power Cylinder above. If this test shows less leak oil, an
inside leak in power cylinders is indicated.
Testing Hydraulic Function of Steering and Engine-driven Pump in Steering
Remove pressure and return lines from valve housing of steering circuit II and connect to valve
housing of steering circuit I (upper valve). Vent steering system and run oil temperature to approx.
50º C. Perform function test as described under Para. 8.1.5 for steering circuit II.
Testing Hydraulic Function of Steering and Drive-dependant Pump (Emergency
Steering Pump) in Steering Circuit I
The following section shows testing of steering circuit I with drive-
dependent pump (emergency steering pump) on rolling vehicle with
engine stopped. Testing of engine-driven pump (steering systems with
1 or 2 engine-dependent and 1 drive-dependent pumps) proceeds
with engine running at vehicle stopped (refer to Paras. 8.1.5. and
Run vehicle at a speed of 30 km/h
Move gear shift lever to neutral and push engine shutoff button until indicator lamp for steering
circuit I lights up.
Turn steering wheel repeatedly 1/4 to 1/2 turn to the right and left. The steering should move
"easily"; actuating force approx. 50 N at a steering wheel diameter of 500 mm. These
measurements must be performed within a speed range from 25 to 10 km/h. If the drive-
dependent pump is no longer operational, the vehicle can no longer be steered (actuating
force more than 250 N at a steering wheel diameter of 500 mm).
Upon completion of the inspection jobs, a test drive should be made to check the vehicle or the
steering system for perfect operation and absence of external leaks.