The hydraulic system powers the hydraulic cylinder, which raises and lowers the dump body.
Major components of the hydraulic system are:
The gear pump is mounted directly to the vehicle PTO. It supplies the system with a working pressure of 2,500 psi
(17,238 kPa), with approximately 1,200 rpm input speed from the PTO.
There is one port at the rear of the pump. It is connected to the bottom of the reservoir and receives, through a
suction hose, hydraulic fluid from the reservoir.
The control valve is an integral part of the hydraulic pump. It is a single spool type, with the control spool linked
mechanically to the hydraulic control lever in the cab.
When the hydraulic control lever is pulled back, the control valve routes hydraulic fluid through port B to the
hydraulic cylinder. This extends the cylinder and raises the dump body.
When the hydraulic control lever is pushed forward, the control valve routes hydraulic fluid through port A to the
hydraulic cylinder. This retracts the hydraulic cylinder and lowers the dump body.
A third control valve port returns hydraulic fluid through the filter and into the reservoir.
The control valve has a relief valve which is set at 2,500 psi (17,238 kPa).
The hydraulic cylinder is a three-stage telescoping cylinder with a 124 in. (315 cm) stroke.
The bottom of the hydraulic cylinder is attached by a pivot pin to the cylinder support frame.
The collar of the hydraulic cylinder is attached by pivot pins to the dump body inside the long beam at the front of
the dump body.
The pivot pins at the top and bottom of the cylinder allow the cylinder to pivot as it is extended and retracted.
Composite lubrication-free bearings at these pivot points ensure smooth, maintenance-free operation.
The filter is located on top of the reservoir. It filters hydraulic fluid as it returns to the reservoir through the return
line from the control valve.
The filter element is made of 10-micron synthetic material. A filter service indicator gauge indicates when the filter
The filter has a bypass feature.
The reservoir is an all-steel container with a 12.75 gal. (48.2 l) capacity.
It is mounted upright, bolted to the hydraulic cylinder mount, between the hydraulic cylinder and the vehicle cab.
The fill cap is also a breather and a strainer. It must be kept clean at all times.
The oil level in the reservoir can be seen through the sight tube on the outside of the reservoir. An oil level decal,
mounted adjacent to the sight tube, is marked FULL, ADD 2 QTS, and ADD 1 GAL.