W20ZA W25ZA [A495]
4000 SRM 1046
Before working on or near the mast, see Safety
Procedures When Working Near Mast in this
This section contains the removal, installation, and
adjustment procedures for the two-stage, zero free-
lift mast. The description and operation of the mast
is outlined in the section Mast Description 4000
The repair procedures for the W20ZA and W25ZA
masts are outlined in this section.
The main components of the mast include:
• Mast Weldments
• Lift Cylinders
• Lift Chains
• Hydraulic Tubing
The mast assembly has wear strips and shims that
prevent wear to the mast weldments and allow for
limited adjustment. The wear strips are replaceable
components where friction points cannot be avoided,
such as the outside edge of the channel flange. Load
rollers sustain the forward and backward forces on
the mast and carriage while reducing friction on the
mast weldments. Wear strips must be shimmed peri-
odically, however, no adjustment is necessary for load
rollers. Both may be replaced when necessary. Refer
to Mast Repair, Remove.
The mast and carriage assemblies and their
components are heavy. To help prevent dam-
age or injury, a lifting device must be used
during all service procedures.
The mast assemblies must have the mast weldments
parallel with equal clearance on each side between
all weldments. Correct operation depends on peri-
odic cleaning, lubrication, shimming the wear strips,
and adjustment of the lift chains.
NOTE: For the proper maintenance and inspection
procedures for the mast, hydraulic cylinders, forks,
chains, and carriages for your truck, see Periodic
Maintenance 8000 SRM 1048.
NOTE: The carriage can be removed from the mast
assembly with the load backrest and forks installed.
Likewise, the mast can be removed from the truck
without removing the carriage. Perform only the pro-
cedures necessary for repair.