Hyster MAST N30XMH, Repair Manual

Page: 19 / 52

4000 SRM 482 Two-Stage Mast Assembly
Legend for Figure 14
1. CAPSCREW
2. WASHER
3. LIFT CYLINDER
4. FITTING
5. TUBE
6. FITTING
7. FLOW REGULATOR
8. HOUSING
9. FITTING
10. CAPSCREW
Remove
NOTE: It is not necessary to remove the mast assem-
bly from the truck to remove the lift cylinder.
1. Move lift truck to a safe, level area.
2. Block wheels to prevent movement of lift truck.
3. Remove load backrest from carriage.
4. Raise the inner mast weldment high enough to
align the crossmember with the crossmember of
the outer mast weldment.
WARNING
To prevent possible personal injury or damage
to equipment, always install a safety chain to
restrain the moving parts of the mast.
5. Install a safety chain around the two crossmem-
bers. See Safety Procedures When Working Near
Mast.
6. Remove capscrew, washer, and lockwasher that
hold bottom of lift cylinder to mast.
7. Remove safety chain.
8. Lower carriage completely so that forks rest on
the floor. This will relieve the hydraulic pressure
on the lift cylinder and strain on the lift chains.
9. Place a drip pan under mast and carriage.
WARNING
Hydraulic oil in hoses may still be under high
pressure even though the mast is fully lowered.
To prevent possible injury, slowly loosen hose
connections.
10. Slowly loosen hydraulic tube and allow excess oil
to drain into drip pan.
CAUTION
To prevent dirt or contaminants from entering
the hydraulic system, always install caps on
the tube and flow regulator.
11. Remove hydraulic tube from lift cylinder. Install
caps on the tube and flow regulator.
12. Clean up spilled oil.
13. Remove lift chains from cylinder and chain
sheaves.
14. Install a sling around the cylinder at the chain
weldment.
15. Attach the sling to a crane or other suitable lift-
ing device to support the cylinder.
16. Remove two capscrews and lockwashers that
hold support bracket to inner mast weldment.
17. Using the crane, tilt cylinder forward and lift
cylinder out of mast weldment.
Install
1. Using the crane, align base of cylinder with lower
crossmember of outer mast weldment.
2. Tilt lift cylinder backward and align support
bracket with two screw holes in inner mast
weldment.
3. Install two capscrews and lockwashers that hold
support bracket to inner mast weldment.
4. Align base of cylinder with screw hole in lower
crossmember of outer mast weldment.
5. Install capscrew, washer, and lockwasher that
hold bottom of lift cylinder to mast.
6. Remove caps on the tube and flow regulator.
7. Install tube on flow regulator.
8. Clean up spilled oil.
9. Place lift chains over the top of the chain sheaves.
10. Install lift chains to chain anchors.
11. Exercise cylinder by raising and lowering mast
several times.
12. Check hydraulic oil level in tank and fill to proper
level if necessary.
15