Service and Maintenance Manual
Service and Maintenance Manual - JLG
Service and Maintenance Manual - JLG
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SECTION 2 - SERVICE PROCEDURES<br />
2.12 MAST TO BASE FRAME INSTALLATION<br />
1. Using an overhead crane or suitable lifting device<br />
capable of supporting the weight of base frame,<br />
attach a sling strap or chain to the front crossmember<br />
of the base frame, raise base frame.<br />
2. Extend hydraulic cylinder out from bottom of mast<br />
assembly approximately one (1) foot. (Caps on<br />
extend <strong>and</strong> return ports will need to be removed to<br />
extend cylinder. Catch any hydraulic fluid expelled<br />
from return port in a container to prevent spillage<br />
onto work area).<br />
3. Bring base frame into position in front of mast<br />
assembly, (base frame <strong>and</strong> mast assembly must be<br />
held at 90° angle to each other).<br />
4. Slide port end of hydraulic cylinder through hole in<br />
base frame cylinder mounting channel. (Return port<br />
(tube side) of cylinder must be on right side facing<br />
bottom of base <strong>and</strong> mast).<br />
5. Align threaded hole in side of hydraulic cylinder<br />
head with hole in tab on bottom side of cylinder<br />
mounting channel. Secure hydraulic cylinder to cylinder<br />
mounting channel tab using a 5/16"-18UNC x<br />
5/8" long hex head bolt <strong>and</strong> flat washer.<br />
6. Carefully push mast assembly <strong>and</strong> base assembly<br />
together until the four (4) holes on bottom rear of<br />
mast align with holes in the base frame mast support<br />
crossmember.<br />
7. Attach mast to base using four (4) 3/8"-16UNC x 1"<br />
long hex head bolts, locknuts <strong>and</strong> flatwashers,<br />
(place a flatwasher under bolt head <strong>and</strong> nut <strong>and</strong><br />
mount with nuts on inside of frame).<br />
8. Locate the two (2) mast support braces, attach to<br />
sides of base frame using a 3/8"-16UNC x 1" long<br />
hex head bolt, nut <strong>and</strong> flatwashers each brace,<br />
(place a flatwasher under bolt head <strong>and</strong> nut <strong>and</strong><br />
mount with nuts on inside of frame. Use access hole<br />
in bottom of frame to attach nut inside frame).<br />
9. Before setting machine upright on base, install a<br />
short 90° elbow fitting, flow control valve <strong>and</strong><br />
another short 90° elbow fitting on the end of the flow<br />
control valve in the extend (left) port on bottom of<br />
hydraulic cylinder. Install a long 90° elbow fitting on<br />
return (right) port. Use sealant tape on fitting<br />
threads. Cap ports until hydraulic lines are installed.<br />
10. Carefully set machine in an upright position on its<br />
base frame wheels.<br />
11. Locate the mast support bracket. Attach mast support<br />
bracket to mounting holes halfway up back of<br />
mast using four (4) 3/8"-16UNC x 2-3/4" long hex<br />
head bolts, locknuts <strong>and</strong> flatwashers. (Place a flatwasher<br />
under bolt head <strong>and</strong> nut <strong>and</strong> mount with nuts<br />
on inside of frame).<br />
12. Using a 4 ft. level, ensure mast is set to vertical<br />
(plumb) on the base frame.<br />
13. When mast is vertical (plumb), attach support<br />
braces, (bolted to base), to the mast support<br />
bracket, (bolted to mast), using 3/8"-16UNC x 2-3/4"<br />
long hex head bolts, nuts <strong>and</strong> flatwashers. (Place a<br />
flatwasher under bolt head <strong>and</strong> nut <strong>and</strong> mount with<br />
nuts on inside of bracket).<br />
14. After securing mast to base frame, using 4 ft. level<br />
again check that mast is vertical (plumb) on base<br />
frame.<br />
Mast installation should now be complete.<br />
2-30 – JLG Lift – 3120875