SkyTrak 6036 Service Manual - Manual (Page 169)

Section 9 Hydraulic System
Model 6036/6036T S/N 9B0500 thru 14833 9-19
b. Grille Tilt Cylinder, Slave Cylinder and
Raise Cylinder Interaction
The slave cylinder is mounted to the boom in a way
that is similar to the raise cylinders, Fig. 9.12.
When the boom is raised or lowered, the movement
of the slave cylinder follows the movement of the
raise cylinders. The slave cylinder shares a
common extend hydraulic line with the grille tilt
cylinder, and also a common retract line. The
movements of the cylinders are interactive.
When the boom is raised, the slave cylinder is
extended which causes pressure buildup on the rod
end of the piston. This pressure pilots open the
counterbalance valve, Fig. 9.12, and forces
hydraulic oil to flow from the rod end of the slave
cylinder to the rod end of the grille tilt cylinder and
from the base end of the grille tilt cylinder to the
base end of the slave cylinder. The fork tilt
cylinder rod retracts to tilt the grille down and
compensate for upward boom movement. The
amount of grille tilt cylinder rod movement is
proportional to slave cylinder rod movement to
always keep the grille at the same attitude.
When the boom is lowered, the slave cylinder is
retracted which causes pressure buildup on the
base end of the piston. Hydraulic oil flow and
cylinder and grille action are just the reverse of
raising the boom. Oil flows through the pilot-
counterbalance valve without piloting.
c. Pressure Checks and Adjustments
Grille Tilt “Up” Relief Valve
1. Engage the park lock, place the travel select
lever in neutral, and stop the engine.
3. Remove the transmission cover from the
frame.
Warning
Wait for the hydraulic fluid to cool before serv-
icing any hydraulic component. Hot hydraulic
fluid can cause severe burns.
4. Install a tee and pressure gauge capable of
measuring 0-4000 psi
(275,6 bar) at the 15 gpm
section of the tandem pump, Fig. 9.12.
5. Start the engine. Operate the grille tilt control
several times to purge the system of air.
6. With engine at idle, place the grille and frame
tilt control lever in the “up” position and hold
until the grille tilt cylinder has fully extended.
Continue holding the lever in the “up” position
until the pressure readings are taken.
Before starting the engine be sure all hydraulic
connections are tight and all tools are removed
from the forklift.
Warning
7. Check the pressure gauge reading. It should
read 2700 -100/+150 (186 -6,9/+10,3 bar). If
not, adjust the grille tilt “up” relief valve, Fig.
9.12, 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 con-
trols 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. Operate the grille tilt control
fully several times to purge the system of air.
11. Install the transmission cover after adjustment.
Grille Tilt “Down” Relief Valve
2. Operate the hydraulic controls after the engine
has stopped to relieve any trapped pressure.
Warning
Relieve hydraulic pressure before servicing any
hydraulic component. Escaping hydraulic fluid
under pressure can penetrate the skin causing
serious injury.