Master Cylinder; Removal; Disassembly; Assembly - Upright AB46 I Service & Parts Manual

Section
3.15

3.15 Master Cylinder

REMOVAL

1. Raise elevating assembly until master cylinder pins
are accessible.
2. Support the cage assembly (refer to Figure 3-1).
3. Remove rod end retaining bolt and rod end pin.
4. Mark and disconnect hoses and immediately cap
the openings to prevent contamination.
5. Using a metal drift, remove rod end pin.
6. Remove base end pin retaining bolt and pin.
7. Carefully remove master 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 be visible to the naked
eye.
1. Remove set screw from cylinder tube and unscrew
head from cylinder.
2. Carefully pull rod assembly from cylinder.
3. Clamp rod end in vise 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 the rod, head, piston, and tube for
scratches, pits, or polishing. 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.
3-24
Maintenance
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 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. Be sure hole for set
screw aligns with hole in cylinder tube.
9. Clean set screw in loctite primer. Install set screw
using loctite #242.

INSTALLATION

1. Follow steps from "REMOVAL" section in reverse
order to install cylinder.
2. Remove boom support.
3. Slowly raise and lower boom several times. Check
hydraulic connections for leaks. Check for proper
slave cylinder operation.
A. Rod
B. Head
C. Piston
D. Cylinder
E. Set Screw
Seal kit (068454-010) includes:
1. Rod Wiper
2. Rod Seal
Figure 3-24: Master Cylinder
AB46 Work Platform
3. Backup
4. Static Seal
5. Piston Seal