Section 4 • Repair Procedures
REV A
November 2005
Part No. 84700
GR-12 • GR-15 • GR-20
4 - 31
4 Turn the key switch to platform control and pull
out the red Emergency Stop button to the on
position at both the ground and platform
controls.
5 Activate the function enable switch and press
and hold the steer thumb rocker switch to the
right. Allow the wheels to completely turn to the
right. Continue holding the switch while
observing the pressure reading on the pressure
gauge. Note the pressure. Refer to Section 2,
Specifications.
6 Press and hold the steer thumb rocker switch to
the left. Allow the wheels to completely turn to
the left. Continue holding the switch while
observing the pressure reading on the pressure
gauge.
7 Turn the machine off. Hold the steer relief valve
with a wrench and remove the cap (schematic
item G).
8 Adjust the internal hex socket. Turn it clockwise
to increase the pressure or counterclockwise to
decrease the pressure.
Component damage hazard. Do
not adjust the relief valve
pressures higher than
specifications.
9 Install the relief valve cap.
10 Repeat steps 5 through 6 to confirm the relief
valve pressure.
FUNCTION MANIFOLD
6-3
Valve Coils
How to Test a Coil
A properly functioning coil provides an
electromotive force which operates the solenoid
valve. Critical to normal operation is continuity
within the coil that providess this force field.
Electrocution hazard. Contact with
electrically charged circuits could
result in death or serious injury.
Remove all rings, watches and
other jewelry.
1 Tag and disconnect the wire harness from the
coil to be tested.
2 Test the coil resistance.
Result: The resistance should be within
specification, plus or minus 30%.
Result: If the resistance is not within
specification, plus or minus 30%, replace the
coil.
Valve Coil Resistance Specifications
Description
Specification
Solenoid valve, 3 position 4 way
18 to 21
Ω
20V DC with diode (schematic items E)
Solenoid valve, 3 position 4 way
25 to 28
Ω
20V DC with diode (schematic item F)
Solenoid valve, 2 position 4 way
18 to 21
Ω
20V DC with diode (schematic item H)
Solenoid valve, 2 position 2 way N.C.
7.5 to 10.5
Ω
with manual override
12V DC with diode (schematic item N)
