SECTION 2 - PROCEDURES
2-28
– JLG Lift –
3120743
2.11 CYLINDER REMOVAL AND
INSTALLATION.
Upper (Main) Boom Lift Cylinder Removal.
(See Figure 2-24)
1.
30/35/n35 electric - Place the machine on a flat and
level surface. Place the Upper Boom in a horizontal
position. Shut down machine and prop boom.
40/n40/45 electric - Place the machine on a flat and
level surface. Place the Upper Boom in a horizontal
position. Place Lower and Mid Booms 5 degree
above horizontal. Shut down machine and prop
boom.
2.
Tag, disconnect and cap the upper boom lift cylinder
hydraulic lines and ports.
3.
Remove the hardware securing the cylinder rod
attach pin #1 to the boom. Using a suitable brass
drift, drive out the cylinder rod attach pin #1.
4.
Secure the cylinder with suitable slings or supports
as required. Remove the hardware securing the bar-
rel end attach pin #2. Using a suitable brass drift,
drive out the barrel end attach pin #2.
5.
Remove the cylinder from the boom and place in a
suitable work area.
Upper (Main) Boom Lift Cylinder Installation.
NOTE:
Coat I.D. of bushings with specified lubricant prior to
installing pins.
1.
30/35/n35/40/n40/45 electric - Install Lift Cylinder in
place using suitable slings or supports, aligning
attach pin mounting holes on upright.
2.
Using a suitable drift, drive the barrel end attach pin
#2 through the mounting holes in the lift cylinder
and upright. Secure in place with pin retaining hard-
ware.
3.
Remove cylinder port plugs and hydraulic line caps
and correctly attach lines to cylinder ports.
4.
With function speed switch at its slowest setting,
extend the cylinder rod until attach pin hole aligns
with those in boom. Using a suitable drift, drive the
cylinder rod attach pin #1 through the aligned
holes. Secure the pin in place with pin retaining
hardware.
5.
Cycle cylinder completely to check for proper func-
tioning. Place boom in stowed position. Check
hydraulic fluid level and adjust accordingly.
Table 2-2.Holding Valve Torque Specifications.
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)
Figure 2-24. Upper Boom Lift Cylinder Removal.
Property of American Airlines