Skyjack SJ12 Service Manual

89
SJ12, SJ16
213558ADA
Hydraulic System Adjustments Section 5 – Procedures
5.3 Hydraulic System
Adjustments
All adjustments must be made with a calibrated
gauge. Refer to the serial number plate located on
the rear of the machine for system and lift pressure
values.
5.3-1 System Relief Pressure Adjustment
1. Extend transverse deck to service position, then
raise the service access door and secure in
position with the prop rod provided.
2. Locate system pressure test port on power pack
manifold. Refer to Section 3 Power Pack and
Port Identification for location.
3. Install a calibrated 5000 PSI gauge to the system
pressure test port.
4. Remove platform control box from guardrail and
locate it in the proximity of the work area of the
power pack.
5. At the power pack manifold, loosen locknut on
system relief valve R1. Refer to Section 3 Power
pack and Port Identification for location.
6. Remove wires #15A and #16A from the valve
coils. Refer to Section 3 Power Pack and Port
Identification for location.
7. Select drive with the Lift/Drive switch on the
platform control box.
8. Engage either forward or reverse drive and hold.
Engage diagnostic switch and hold.
9. Observe reading on gauge when drive is
selected. Adjust system relief valve R1 value
listed on the serial number plate. Turn the
stem on the relief valve clockwise to increase
pressure. Turn the stem counterclockwise to
decrease pressure.
10. Release joystick, diagnostic switch and then
tighten the locknut.
11. Reinstall wires #15A and #16A to the valve
coils.
12. Remove the gauge from the system pressure
test port.
13. Store prop rod back to its holder, then lower
service access door and secure it. Push the
transverse deck back to the working position.
5.3-2 Lift Pressure Adjustment
1. Extend transverse deck to service position, then
raise the service access door and secure in
position with the prop rod provided.
2. Locate the hose going to the lift cylinder on
the main manifold. Remove and plug the hose.
Refer to Section 3 Main Manifold Assembly for
location.
3. Install a calibrated 5000 PSI gauge to the port on
the manifold where the hose was disconnected.
4. At the main manifold, loosen the locknut on the
lift relief valve R3.
5. Select lift with the Lift/Drive select switch on the
platform control box.
6. Engage platform lift function and hold. Engage
diagnostic switch and hold.
7. Observe reading on gauge. Adjust lift relief
valve R3 to the value listed on the serial
number plate. Turn the stem of the relief valve
clockwise to increase pressure. Turn the stem
counterclockwise to decrease pressure.
8. Release platform lift function, diagnostic switch
and then tighten the locknut.
9. Remove the gauge from the lift port on the
manifold. Reattach lift cylinder hose and tighten.
10. Store prop rod back to its holder, then lower
Service access door and secure it. Push the
transverse deck back to the working position.
NOTE
Pressure setting may vary as machine
components wear. The lift pressure should be set
for rated load only.

Skyjack SJ12 Specifications

General

Gradeability	25%
Drive Motor	24V DC
Machine Width	32 in (0.81 m)
Stowed Height	6.5 ft
Overall Width	32 in (0.81 m)
Stowed Height (Rails Folded)	6.5 ft
Drive Speed (Elevated)	0.5 mph (0.8 km/h)
Power Source	Electric