HYDRAULIC CONTROL VALVES REPLACEMENT - CONTINUED
HYDRAULIC OIL PRESSURE TESTS
Remove hollow hex plug (1) to the passage for the
pump oil. Install an oil pressure gauge, hose, and fit-
tings in the plug opening.
Start and run the engine at high idle RPM. Move the
control levers that operate the hydraulic cylinders to
get an increase in the temperature of the hydraulic oil.
When the temperature of the hydraulic oil is approxi-
mately 30F (17C) more than the temperature of the
atmosphere, run the engine at high idle RPM. With all
of the control levers in HOLD position, look at the oil
The correct pressure is 2150 + 30 psi (14,824 + 207
kPa). If the pressure of the pump oil is too low, the
pump or the combination valve or both the pump and
the combination valve need repair (WP 0323 00 or
WP 0329 00).
With the engine at high idle RPM, look at the oil pres-
sure gauge and move each control lever separately.
Hold the lever in position after the rod is either, in to,
or out of the cylinder as far as it will move. The cor-
rect pressure is 3550 + 20 psi (24,476 + 136 kPa)
when a control lever is held both forward and to the
If the pressure is too low, make a record of the pressure and the position of the rod, either in, or out of the cylinder. Test
To test the circle drive control, stop engine. Disconnect the two oil lines to the hydraulic motor at the control valve.
Install metal caps on the fittings in the control valve. The caps must keep the oil in the control when it is being tested.
Start and run the engine at high idle RPM. Look at the oil pressure gauge when the control lever is moved, both forward
and to the rear. If the oil pressure is too low, make a record of the position of the control lever and the pressure.
If the oil pressure for both positions of each control lever is too low, the pump or the combination valve, or both the
pump and the combination valve need repair (WP 0323 00 or WP 0329 00).
If the oil pressure for both positions of only one lever is correct and all of the other lever positions have too low oil pres-
sure, the check valve is open in the control valve with the correct oil pressures.
If the oil pressure for one position of a control lever for one valve section is low and the other lever position has correct
oil pressure, there is damage in the resolver valve.
END OF WORK PACKAGE