JLG 80HX_HX+6_HXER ANSI Service Manual User Manual
Page 106
SECTION 5 - HYDRAULICS
5-14
– JLG Lift –
3120271
5.5
CYLINDER REMOVAL AND
INSTALLATION
Telescope Cylinder Removal
1.
Be sure the boom is fully retracted and in a horizon-
tal position.
2.
Shut down the engine. Support the boom basket
end with a prop. (See Figure 5-2.)
3.
Remove the boom end-cover.
HYDRAULIC LINES AND PORTS SHOULD BE CAPPED IMMEDI-
ATELY AFTER DISCONNECTING LINES TO AVOID THE ENTRY OF
CONTAMINANTS INTO THE SYSTEM.
4.
Tag and disconnect the hydraulic lines to the tele-
scope cylinder. Use a suitable container to catch any
residual hydraulic fluid. Cap all hydraulic lines and
ports.
5.
Remove the two snap rings that retain the telescope
cylinder pin to the base boom.
6.
Using a suitable brass drift, carefully drive the tele-
scope cylinder pin from the base boom.
7.
Remove the telescope cylinder trunnion pin covers
from each side of the base boom.
8.
Remove the capscrews securing the trunnion pins
from each side of the boom.
9.
Using a suitable slide hammer, remove the trunnion
pins attaching the telescope cylinder to the mid
boom.
10.
Attach a suitable sling to the telescope cylinder.
Support the cylinder with an overhead crane or
other suitable lifting device.
11.
Remove the two (2) extension chain adjusting nuts
from the eyebolt through the chain adjust assembly.
12.
Remove the four (4) bolts and lock washers attach-
ing the chain attach block to the base boom section
and remove the block.
13.
Using the lifting equipment, raise the telescope cyl-
inder enough to obtain adequate clearance for
removal of the telescope cylinder rod support
bracket.
14.
Remove the cylinder rod support bracket.
15.
Attach a suitable lifting device to the extension chain
adjusting eyebolt above the cylinder rod.
NOTE: The extension chain will come out of the boom twice
as far as the telescope cylinder.
16.
Using both lifting devices, carefully pull the cylinder
from the boom assembly.
17.
As the cylinder is removed from the boom, lay the
extension chain on top of the base boom.
18.
Using another lifting device, support the sheave
wheel end of the cylinder and remove the cylinder
from the boom assembly.
19.
Carefully lift the cylinder clear of the boom assembly
and lower to the ground or suitably supported work
area.
Telescope Cylinder Installation
1.
Using suitable lifting equipment, carefully lower the
cylinder to the boom assembly.
2.
Using another lifting device, support the sheave
wheel, or rod end, of the cylinder and install the cyl-
inder into the boom assembly.
3.
Slide the cylinder into boom, sliding the extension
chain in place as the cylinder is moving in.
4.
Attach a suitable lifting device to the extension chain
adjusting eyebolt.
5.
Attach the cylinder rod support bracket to the rod
support block on the telescope cylinder.
6.
Install the chain adjust block with four (4) lock-
washer and bolts to the base boom section.
7.
Install the two (2) extension chain adjusting nuts that
attach the eyebolt to the chain adjust block.
8.
Remove the lifting device from the telescope cylin-
der.
9.
Using a suitable brass drift install the trunnion pins
attaching the telescope cylinder to the mid boom
section.
10.
Install the capscrews securing the trunnion pins to
each side of the boom. Note that loctite 242 is
required on the capscrew threads.
Table 5-2.Holding Valve Torque Specification
Description
Torque Value
SUN - 7/8 HEX M20 x 1.5 THDS.
30-35 ft.lbs.
(41-48 Nm)
SUN - 1 1/8 HEX 1-14 UNS THDS.
45-50 ft.lbs.
(61-68 Nm)
SUN - 1 1/4 HEX M36 x 2 THDS.
150-160 ft.lbs.
(204-217 Nm)
RACINE - 1 1/8 HEX 1 1/16-12 THDS.
50-55 ft.lbs.
(68-75 Nm)
RACINE - 1 3/8 HEX 1 3/16-12 THDS.
75-80 ft.lbs.
(102-109 Nm)
RACINE - 1 7/8 HEX 1 5/8-12 THDS.
100-110 ft.lbs.
(136-149 Nm)