JLG 120-SXJ ANSI Service Manual - Manual (Page 80)

SECTION 5 - HYDRAULICS
5-8 – JLG Lift – 3121105
IF THE CYLINDER IS TO BE TESTED PRIOR TO INSTALLATION ON
THE MACHINE, EXTREME CARE SHOULD BE USED TO INSURE
THAT THE OUTER END OF THE ROD IS SUPPORTED. USE
EITHER A TRAVELING OVERHEAD HOIST, FORKLIFT, OR OTHER
MEANS TO SUPPORT THE OVERHANGING WEIGHT OF THE
EXTENDING ROD.
NOTE: Steps (17) through (20) apply to the telescope cylin-
der.
17. Elevate the barrel end of the cylinder to a work
bench or other suitable device.
18. Plug the retract port and supply hydraulic power to
the extend port.
19. Open the bleeder port plug (TP), venting all trapped
air to atmosphere. Retighten the bleeder port plug.
Disconnect the hydraulic power source and remove
plug from retract port.
20. An alternative to steps (18) through (20) is to posi-
tion the barrel horizontally in a suitable holding
device, attach a hydraulic power source to both
extend and retract ports, while supporting the cylin-
der rod, cycle the cylinder a minimum of 5 times with
the bleeder port unplugged, venting all trapped air
to atmosphere. A suitable hose may be attached to
the bleeder port with the end in a container suitable
to contain the hydraulic fluid. After all air is vented
remove all attached hoses, and install the bleeder
port plug. Also plug the extend and retract ports until
cylinder is installed in boom.
5.5 PRESSURE SETTING PROCEDURES
Main Valve
1. Main Relief.
a. Plug pressure gauge into quick-connect (G port)
on main valve. Monitor gauge.
b. Bottom out Lift Up function.
c. Loosen nut at main relief and adjust pressure to
3450 psi (238 bar) using an Allen wrench.
Tighten nut.
Table 5-2. Holding Valve Torque Specifications
Description Torque Value
Sun - 7/8 hex M20 x 1.5 thds 30-35 ft. lb.
(41-48 Nm)
Sun - 1-1/8 hex 1-14 UNS thds 45-50 ft. lb.
(61-68 Nm)
Sun - 1-1/4 hex M36 x 2 thds 150-160 ft. lb.
(204-217 Nm)
Racine - 1-1/8 hex 1-1/16 - 12 thds 50-55 ft. lb.
(68-75 Nm)
Racine - 1-3/8 hex 1-3/16 - 12 thds 75-80 ft. lb.
(102-109 Nm)
Racine - 1-7/8 hex 1-5/8 - 12 thds 100-110 ft. lb.
(136-149 Nm)