4000 SRM 764
Three-Stage Mast
4.
Use a pry bar to move the inner mast weldment
approximately 1/2 to 3/4 out of the intermedi-
ate mast weldment. Remove the snap rings and
washers from the top of each main-lift cylinder.
Move the intermediate mast weldment approx-
imately 152 to 305 mm (6 to 12 in.) out from
the top of the outer mast weldment. Remove the
chain and remove the hose sheaves at the top of
the intermediate mast weldment.
5.
Install a sling near the center of each channel of
the inner mast weldment so it will be balanced.
The slings must pass through the loop at the end
of the sling so the sling tightens and does not slip
on the channel as the weldment is lifted. Fasten
a crane to the slings.
6.
Use the crane to move the inner mast weldment
out of the outer mast weldment. Move the mast
weldment until the bottom rollers of the inner
mast weldment touch the top rollers of the outer
mast weldment. Use the crane to raise the top
of the inner mast weldment so it is at an angle
of approximately 30°. Lift the weldment straight
up to remove the inner from the outer mast weld-
ment. Put the weldment flat on the floor so it
cannot fall.
7.
Use the procedure of Step 5 and Step 6 to remove
the intermediate mast weldment from the outer
mast weldment.
8.
Clean the area at the hydraulic fittings for the
main-lift cylinders. Disconnect the fittings. Put
caps on the open fittings and cylinder port to pre-
vent dirt from entering the system. Remove the
snap rings at the bottom of each cylinder.
9.
Install a sling near the center of one main-lift
cylinder in the same manner used for the mast
weldment removal.
Remove the capscrew,
washer, and spacer that fasten the cylinder to
the outer mast channel. See Figure 3. Use the
crane to move the cylinder out of the base hole
and remove the cylinder from the mast. Repeat
the procedure to remove the other main-lift
cylinder.
10. Remove the snap rings from all load rollers.
Make a note of the shim arrangement as each
load roller is removed. Remove the snap rings
from all the sheaves. Make a note of the shim
arrangement as each sheave is removed.
All
shim arrangements will be approximately the
same when the mast is assembled.
11. Remove the strip bearings from the outer mast
weldment. Make a note of the shim arrangement
during removal of the strip bearings for correct
installation during assembly.
12. Disassemble the sheaves and rollers as necessary
for repair and cleaning.
CLEAN AND INSPECT
The procedures for cleaning and inspecting the three-
stage masts are the same as the procedures for the
two-stage masts. See Clean and Inspect for the Two-
Stage Mast for the correct procedures.
LIFT CYLINDERS
NOTE:
The lift cylinders are removed during disas-
sembly of the mast. To repair the cylinders, see the
section Lift Cylinders 4000 SRM 135 for the correct
service procedures.
ASSEMBLE
NOTE:
The shims for the load rollers keep the chan-
nels of the mast weldments parallel and give correct
clearance. During assembly, the arrangement of the
shims will be the same or approximately the same as
they were before disassembly. Check the clearance
and adjust for wear or changes from the repairs. The
strip bearings at the top of the outer mast weldment
and the bottom of the inner mast weldment are also
adjusted using shims. See the Checks and Adjust-
ments in this section for the instructions to make the
necessary adjustments. See Figure 4 and Figure 12.
1.
Assemble the load rollers, sheaves, and strip
bearings on the mast weldments and operator
platform as necessary.
Assemble the sheaves
on the free-lift cylinder. Make sure to keep the
same shim arrangement noted during disassem-
bly. Apply a thin layer of multipurpose grease
to the strip bearings and the bearing and roller
surfaces of the channels.
2.
Make sure the cylinders are assembled and in-
stall a sling near the center of one main-lift cylin-
der as during removal. Use a crane to move the
cylinder into position in the outer mast weld-
ment.
Install the snap ring on the bottom of
the cylinder. Install the capscrew, washer, and
spacer to fasten the cylinder shell to the chan-
nel. Repeat the procedure to install the other
main-lift cylinder.
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