JLG 1230ES Service And Maintenance Manual Download

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SECTION 6 - MAST COMPONENTS

6-18

– JLG Lift –

3121222

Cylinder #2 and #3 Assembly to Cylinder #1

Replace the o-rings in the cylinder joint and rod
attach cap. Lubricate the o-rings with hydraulic
oil, however keep any oil off of the threads in the
rod attach cap.

NOTE:

The attach cap threads need to be clean and free of
oil when assembled to the cylinder rod, so the loctite
applied to the cylinder rod threads will set properly.

Lay cylinder #1 assembly and cylinder #2/3
assembly on the workbench in their approxi-
mate assembled position.

At the bottom end of the cylinder #2/3 assembly,
locate the hole on the side of the tapered cylin-
der rod end on cylinder #2. This hole should be
closely aligned with the hole passage inside the
cylinder joint of cylinder #1 assembly when
assembled.

(See Figure 6-21.)

Just before final assembly apply Loctite #242 to
the threads on the tapered end of the cylinder
rod of the cylinder #2/3 assembly. Slide the cylin-
der #2/3 assembly tapered cylinder rod end into
the cylinder joint attached to cylinder #1 align-
ing the hole in the tapered cylinder rod end to
the hole in the cylinder joint.

Install the rod attach cap to the tapered end of
the cylinder rod and torque the cap to 200 Nm
(45 ft. lb.).

Valve Body Installation

PROTECT THE CYLINDER ROD SURFACE. DAMAGE TO THE CYLINDER
ROD CHROME FINISH DUE TO SCRATCHING, INDENTATION, CHIPPING
OR OTHERWISE WILL CAUSE EVENTUAL GLAND SEAL FAILURE. THE
CYLINDER ROD MUST BE REPLACED IF DAMAGED.

Lubricate and place a new o-ring in the groove
on the tapered end of cylinder rod #1.

NOTE:

The cylinder rod and valve body threads need to be
clean and free of oil when the valve body is assem-
bled to the cylinder assembly, so the loctite applied
to the cylinder rod threads will set properly.

Clean the threads of the tapered end of the cyl-
inder rod of cylinder #1 and apply Loctite #242
to the threads.

Apply a light film of hydraulic oil to the rod sur-
face above the threaded area to lubricate the o-
ring when installing the valve body to the cylin-
der rod end.

Be certain the threads inside the valve body are
clean and dry of any debris or oil.

Using the proper fixture to keep the cylinder rod
from turning and protect the cylinder rod from
damage, insert the valve body onto the end of
the cylinder rod and tighten, then torque to 200
Nm (45 ft. lb.).

Hydraulic Cylinder Assembly Testing

If a hydraulic cylinder testing fixture is not available to
fully pressurize the cylinder, then the cylinder must be
checked for proper operation and leaks after installation
of the mast assembly to the machine.

IF A TEST FIXTURE IS USED TO TEST THE HYDRAULIC CYLINDER, DO
NOT EXCEED THE MAXIMUM RATED PRESSURE SETTING OF THE
HYDRAULIC SYSTEM. (SEE SECTION-1 SPECIFICATIONS FOR MAXIMUM
HYDRAULIC SYSTEM PRESSURE SETTINGS.)

Figure 6-21. Cyl. #2/3 to Cylinder Joint Assembly

Cyl. #2 - Cylinder Rod

Cyl. #2 - Hole in Rod

Passage Hole in Joint

Cyl. #1 - Cylinder Rod