Upright AB46 C, Service & Parts Manual

Page: 46 / 148

Section
3-28 AB46 Work Platform
Maintenance
3.19 Jib Cylinder
REMOVAL
1. Using an overhead hoist or crane, support the cage
assembly at a convenient working height.
2. Mark and disconnect hoses and immediately cap
the openings to prevent contamination.
3. Remove hardware which secures jib cylinder pins.
NOTE: Jib cylinder is heavy. Take appropriate mea-
sures to support cylinder.
4. Remove jib cylinder pins. Remove jib cylinder.
DISASSEMBLY
Note: Provide a clean work area for this operation,
and observe clean assembly practices. Seals and
hydraulic cylinder components are highly sensitive to
contamination that may not even be visible to the
naked eye.
1. Remove counterbalance valve from cylinder.
2. Unscrew head from cylinder.
3. Carefully pull shaft assembly from cylinder.
4. Secure rod end and turn piston off of rod.
NOTE: Piston is loctited (Loctite #277) onto rod.
4. Slide the head off of the rod.
5. Remove seal kit components (wipers, rod seals, o-
rings and backup rings) from head and piston.
6. Thoroughly clean all parts with solvent. Rinse the
inside of the tube and allow to drain. A high pres-
sure rinse and wipe with a lint free rag is preferable.
7. Inspect cylinder parts for scratches, pits, or polish-
ing. Check seal groves and sealing surfaces.
Scratches or pits deep enough to catch the fingernail
are unacceptable, replace the cylinder. Polishing is
a sign of uneven loading. When this occurs, the
surface should be checked for roundness. Cylinders
not round within .007" should be replaced.
ASSEMBLY
NOTE: Torque all hardware to torques listed on page
3-32 unless otherwise specified.
1. Lubricate all components and seals with clean
hydraulic oil prior to assembly.
Note: To avoid cutting the seals, do not use sharp
edged tools during seal replacement. After installing
seals allow at least one hour for the seals to elasti-
cally restore to their original shape before assembling
cylinder.
2. Install new seal kit items to piston and head.
3. Lubricate rod wiper and seal with hydraulic oil and
slide head onto rod.
4. Clean threaded end of rod using loctite primer.
5. Using loctite #277, install piston onto rod.
6. Lubricate seals on piston and head with hydraulic
oil.
7. Carefully slide rod assembly into cylinder.
8. Thread head into cylinder.
INSTALLATION
1. Follow steps from "REMOVAL" section in reverse
order to install cylinder.
2. Slowly cycle jib cylinder several times. Check
hydraulic connections for leaks. Check for proper
cylinder operation.
Figure 3-28: Jib Cylinder
1. Piston Seal
2. Wear Ring
3. Rod Wiper
4. Rod Seal
5. Static Seal
A. Rod
B. Head
C. Piston
D. Cylinder
E. Set Screw
3.19
Seal kit (068453-010) includes: