4000 SRM 482
Three-Stage Mast Assembly
the correct snap ring pliers and wear eye and
face protection during removal or installation.
5.
Use a crane and sling to support the cylinder.
Remove the snap ring, backup washer, rubber
bushing, and shims (if applicable) that fasten the
cylinder rod to the intermediate weldment. See
Figure 12. If shims are used, make a note of the
shim arrangement. Normally, the shim arrange-
ment for the replacement cylinder will be similar.
6.
Move the hoist handle forward until the hoist
cylinder is fully retracted and all pressure is re-
lieved from the lift circuit.
7.
Remove the hose or tube between the main cylin-
der and the flow regulator. See Figure 18. If nec-
essary, use a pry bar to carefully move the car-
riage and mast weldments for access. Install a
cap on the regulator fitting to prevent leakage.
8.
Place a winch chain between the stationary up-
right and the overhead guard.
9.
Remove the tilt rod pins.
10. Using the winch chain, allow the mast to tilt far
enough forward to lift the cylinder off the dowel
pins and out of the truck.
11. Push the cylinder toward the top of the mast as-
sembly to move the main cylinder off the locating
dowel pin. Continue to push the cylinder until
the rod moves into the cylinder to allow removal
from the intermediate weldment.
12. Repeat the Step 2 through Step 11 to remove the
other main cylinder.
NOTE:
See the section Lift Cylinders 4000 SRM 481
to disassemble and repair the cylinder.
13. Reverse the procedure to install the main cylin-
ders.
14. If a cylinder is replaced, it may be necessary to
re-shim both cylinders to make sure that the end
stroke (fully extended) is equal on both. This will
prevent racking when the mast is raised to the
maximum fork height. Refer to the appropriate
Parts Manual for the location and correct shim
part numbers.
INNER AND INTERMEDIATE MAST
ASSEMBLIES, REMOVE AND INSTALL
Read and follow the Safety Procedures When Work-
ing Near Mast, as well as all WARNINGS and CAU-
TIONS. See Figure 18, Figure 19, Figure 20, and Fig-
ure 21.
1.
The load rollers and wear plugs must be removed
to remove the inner or intermediate weldments.
See Load Rollers and Wear Plugs, Remove and
Install.
2.
The lift chains, hoses, and electrical cable, if
installed, must also be removed to remove the
inner or intermediate weldments. To remove the
lift chains, hoses, and sheaves, see Three-Stage
Lift Chains, Remove and Install; Hoses, Re-
place; Three-Stage Chain Sheaves, Disassemble
and Assemble; and Hose and Cable Sheaves,
Replace.
3.
Use safety chains to fasten the intermediate
weldment to the outer weldment. Use a crane
or lifting device to support the inner weldment
while sliding it out of the intermediate weld-
ment.
4.
Remove the safety chains that fasten the inter-
mediate weldment to the outer weldment. Use
a crane or lifting device to support the interme-
diate weldment while sliding it out of the outer
weldment.
5.
Reverse the removal procedure to install both the
intermediate and inner weldments into the outer
weldment. Install the load rollers and wear plugs
during assembly of the mast weldments.
29
Summary of Contents for MAST N30XMH
Page 14: ...Two Stage Mast Assembly 4000 SRM 482 Figure 10 Two Stage Mast Assembly Dual Lift Cylinders 10 ...
Page 27: ...4000 SRM 482 Three Stage Mast Assembly Figure 18 Three Stage Mast Assembly 23 ...
Page 34: ...Three Stage Mast Assembly 4000 SRM 482 Figure 21 Hose and Cable Assemblies Outer Weldment 30 ...
Page 51: ......
