Worksaver HPD-16 HSS, Owner'S And Operator'S Manual, Page: 23 / 42

SERVICE INSTRUCTIONS
(continued)
FIG. G
VALVE CONVERSION INSTRUCTIONS
The conversion plug for making the control valve com-
patible with closed-center hydraulic systems is shipped in
the hardware box (see Figure F). DO NOT USE.
FIG. F
NOT USED
ON HSS/P
MODELS
MAINTENANCE AND
ADJUSTMENTS
(continued)
RAM CONTROL HYDRAULIC VALVE
The hydraulic ram control valve supplied with the Post
Driver is “convertible” to accommodate both open-center
and closed-center hydraulic systems. The control valve is
shipped “ready” for open-center hydraulic systems.
NOTE: HSS/P Models require the valve to have the
open center plug.
HYDRAULIC CYLINDER BASE ADJUSTMENT – HPD-16
Due to the design of the Driver carriage, it is necessary
for both the base and rod end of the hydraulic cylinder to
have a slight amount of freedom. This adjustment should
only be necessary if the hydraulic cylinder is removed for
servicing (see Figure G).
The “Special 7/8” Nut” (Part #815205) has the correct
amount of freedom designed in. No adjustment is
required at the rod end of the cylinder rod.
NOTE: These instructions
are for the HPD-16 Models
only.
DISASSEMBLY – CARRIAGE AND RAM ASSEMBLY
1. Lay the driving ram assembly face down on the floor
or on a solid workbench.
2. Remove the transport lock pin. This will allow the ram
carriage to move up, thereby relieving the spring ten-
sion. Disconnect the upper spring bracket.
3. Remove the lock nut from the top of the cylinder rod
using a 1 15 /
16
” wrench and a 1 1 /
2
” wrench on the step
nut and push the rod back into the cylinder.
4. Now remove the hex nuts (or bolts for Models HPD-
22Q and HPD-26Q) holding the transport lock pin
bracket in place. Slide the carriage down and remove
the hydraulic cylinder and springs as a unit from the
lower end.
5. The carriage can now be removed from the upper end
of the ram assembly.
HYDRAULIC CYLINDER DISASSEMBLY
1. Refer to the exploded view of your model post hole
driver and become familiar with the parts and how
they are assembled.
2. It is NOT necessary to remove the complete hydraulic
cylinder to change any of the internal cylinder parts.
These parts can be changed from the top of the cylin-
der. (See following section on replacing the seal).
NOTE: If you need to replace the rod or rod guide, it
may be easier to remove the complete cylinder. This
will allow you to place the cylinder in a vise to remove
the lower part of the cap (gland) from the cylinder
tube.
NOTE: The lower hydraulic cylinder mounting bolts have
stamploc hex nuts ( 3 /
8
” on HPD-16). DO NOT use regular
hex nuts in place of these nuts. They need to be stamploc
nuts. Also, on reassembly, there are instructions on the
proper adjustment of these bolts. See the section on
Hydraulic Cylinder Base and Rod End Adjustment.
(Figure G). (HPD-16 Models only.)
22