THE GAGE AND PIPE MUST BE OF SUCH CONSTRUCTION THAT THEY WILL SAFELY
WITHSTAND THE MAXIMUM PRESSURE THE PUMP CAN PRODUCE.
DO NOT DISCONNECT ANY HOSE CONNECTIONS UNTIL YOU HAVE THOROUGHLY CLEANED
OFF ALL DIRT AND PROMPTLY PLUG THE PORT HOLES TO PREVENT DIRT FROM ENTERING.
With engine running at recommended idle, watch pressure developed as someone tries to steer standing still, first in one
direction and then in the other.
Consult your service manual for the specified pump relief pressure, maximum.
If the maximum relief valve pressure is reached before reaching the end of piston rod travel, it is certain the pump is
developing full hydraulic pressure, also that the control valve is functioning properly and pressurizing the power cylinder;
therefore, the trouble is not in the hydraulic circuit. Check the other causes of hard steering which are listed. If, however ,
the maximum relief valve pressure is not reached and steering is hard, the system is not developing full power. This may
be due to malfunctioning of the pump, valve, or cylinder. Determine which is at fault.
First check the pump. Install a shut-off valve in the pump-to-valve outlet line and locate it next to the pressure gage and
between it and the valve.
THE SHUT-OFF VALVE MUST BE A HIGH PRESSURE TYPE TO WITHSTAND THE MAXIMUM
PRESSURE THE PUMP CAN PRODUCE. AN ORDINARY PLUMBING VALVE SHOULD NOT BE
With the shut-off valve open there is no restriction of flow from the pump.
Close the shut-off valve to test the ability of the pump to produce maximum pressure.
With the engine running at recommended idle speed, gradually close the shut-off valve.
DO NOT LEAVE SHUT-OFF VALVE CLOSED FOR MORE THAN 15 SECONDS. YOU MAY CAUSE
QUICK HEATING OF OIL TO A HIGH DEGREE WHICH CAN CAUSE DAMAGE TO THE PUMP, OIL
SEALS, HOSES, AND FILTER IN RESERVOIR.
If the gage shows the specified maximum pressure, the pump is producing the required pressure. If not, it may be due to
a loose belt, or the pressure relief valve may be sticking open, or the pump may be in need of repairs. If the belt is not
loose or glazed, disassemble the pump and inspect. See pump inspection.
When it is certain the pump is producing the required maximum pressure, next test the valve for pressurizing the cylinder.
Disconnect one of the hoses at one of the cylinder ports and cap the end of the hose and plug to the cylinder port, but first
clean off the dirt and make sure no dirt gets into the port holes.