SkyTrak 6036 Service Manual - Manual (Page 120)

Section 9. Hydraulic System
9-7 Model 6036 S/N 9B0499 and Before
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 “extend“ position and hold
until the extend cylinder has fully extended.
Continue holding the joystick in the “extend”
position until the pressure readings are taken.
7. Check the pressure gauge reading. It should
read 2650 ± 50 psi (182,6 ± 3,4 bar). If not,
adjust the boom extend port relief valve, Fig.
9.2, 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 (13,5 ± 2 N m) 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.
Boom Retract Port Relief Valve
1. Engage the park lock, place the travel select
lever in neutral, level the boom and stop the
engine.
2. Operate the hydraulic controls after the engine
has stopped to relieve any trapped pressure.
Warning !
Warning !
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. 9.3.
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 2650 ± 50 psi (182,6 ± 3,4 bar). If not,
adjust the boom retract port relief valve, Fig.
9.2, 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 (13,5 ± 2 N m) 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
12 to 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 10
to 13 seconds (no load).
Before starting the engine be sure all hydraulic
connections are tight and all tools are removed
from the forklift.
Warning !
Relieve hydraulic pressure before servicing any
hydraulic component. Escaping hydraulic fluid
under pressure can penetrate the skin causing
serious injury.
Wait for the hydraulic fluid to cool before servic-
ing any hydraulic component. Hot hydraulic fluid
can cause severe burns.