SkyTrak 6036 Service Manual - Manual (Page 160)

Section 9 Hydraulic System
9-10 Model 6036/6036T S/N 9B0500 thru 14833
3. Remove the transmission cover from the
frame.
4. Install a tee and pressure gauge capable of
measuring 0 - 4000 psi
(275,6 bar) in the
tandem pump outlet of the 30 gpm section,
Fig. 9.5.
5. Start the engine. Extend and retract the boom
several times to purge the system of air.
6. Depress the accelerator to full throttle. Place
the joystick in the “retract” position and hold
until the extend cylinder has fully retracted.
Continue holding the joystick in the “retract”
position until the pressure readings are taken.
7. Check the pressure gauge reading. It should
read 2850 ± 50 psi
(196,4 ± 3,4 bar). If not,
adjust the boom retract port relief valve, Fig.
9.3, by turning the adjustment screw clockwise
to increase pressure or counterclockwise to
decrease pressure. Torque nuts on relief
valve to 10 ± 1.5 lb-ft (13 ± 2 Nm) after
adjustment.
8. Stop the engine. Operate the hydraulic
controls after the engine has stopped to
relieve any trapped pressure.
9. Remove the pressure gauge and tee from the
tandem pump and reconnect the hydraulic
line.
10. Start the engine. Extend and retract the boom
fully several times to purge the system of air.
11. Install the transmission cover after adjustment.
c. Testing
The boom extend/retract circuit should be tested
whenever repairs or adjustments are made to
components of the circuit.
1. Start the engine, park the forklift on level
ground and level the frame.
2. Check for signs of leakage of hydraulic oil
from circuit hoses and other components.
Correct any leakage problem before testing.
3. Extend and retract the boom several times to
purge the system of air.
4. Starting with the boom fully retracted and
level, extend the boom at full engine speed.
The time required for full extension should be
less than 15 seconds (no load).
5. Starting at the fully extended position, retract
the boom at full engine speed. The time
required to retract the boom fully should be
less than 15 seconds (no load).
6. Repeat steps 4 and 5 to recheck performance.
7. If the boom extend/retract circuit test does not
meet performance requirements, locate the
cause of the problem (refer to Troubleshoot-
ing, paragraph 9.8) and correct before putting
the vehicle into service.
9.3 MAIN CONTROL VALVE
OPERATION
ELECTRONIC CONTROL
9.3.1 Electronic
Refer to Section 10, Electrical System.
9.3.2 Control Valve
The control valve has four sections – inlet, outlet
and two working sections, one for raise/lower and
one for extend/retract, Fig. 9.6. The working
sections are mounted between the inlet and outlet
sections to form a valve stack. The supply
pressure passages are common in the stack as
are the return to reservoir and pilot pressure
passages.
Fig. 9.6 Main Control Valve (Electronic Control)
a. Inlet Section
The inlet section of the control valve contains:
• Pressure reducing valve to supply 200 psi
(13,8 bar) pilot pressure to the pulsar
solenoids in the working sections.
• A 43 micron stainless steel wire cloth filter
for the pilot pressure.
• Pressure compensated flow control valve
with pilot-operated relief valve
(paragraph b).
INLET
SECTION
OUTLET
SECTION
EXTEND/
RETRACT
MK0210
RAISE/
LOWER