Operation and maintenance manual

Section 230-0000
SM 1407 Rev 2 11-01
1
BODY SYSTEM - Body System Schematic
DESCRIPTION
Numbers in parentheses refer to Figs. 2 through 5.
Oil supply to the body hoist system is by common
components to both the body and steering systems.
Refer to Section 220-0000, STEERING SYSTEM
SCHEMATIC.
Hydraulic oil is drawn from the hydraulic tank (1) by
the main hydraulic pump and pumped to the flow
amplifier valve via double check valve. A priority spool
within the flow amplifier valve directs oil supply from
the main hydraulic pump to the steering valve, and,
through the 'EF' port to body control valve (2).
A brief description of the individual components shown
in the body hoist system schematic are listed below.
Detailed service and operating instructions can be
found in the relevant component sections of this
manual.
Hydraulic Tank (1)
Refer to Section 230-0040, HYDRAULIC TANK.
The hydraulic tank is the common reservoir for the
steering, braking and body hoist systems. It is
mounted off the frame and fender bracket at the rear
right hand side of the tractor.
Integral with the hydraulic tank assembly are the
hydraulic oil filter, oil strainer and oil level sight gauge.
Located on top of the tank assembly is the filler cap
and breather.
Body Control Valve (2)
Refer to Section 230-0060, BODY CONTROL VALVE.
The single spool body control valve is mounted to the
cradle assembly at the rear of the cab. The control
valve consists of a relief valve assembly and a four
position control spool.
The four positions of the control spool are 'Raise',
'Hold', 'Lower' (Power Down) and 'Float'. The 'Float'
position is detented and the control spool should be
kept in this position at all times, except when Raising
or Lowering the body.
A relief valve assembly at the pressure inlet, opens
and allows oil to flow through hydraulic oil cooler (4)
and back to hydraulic tank (1) when pressure in the
hydraulic system exceeds 172 bar (2 500 lbf/in²).
Movement of the control spool is controlled by
electrical signals from the body control joystick in the
operators compartment. Refer to Section 230-0081,
BODY CONTROL JOYSTICK.
Body Cylinders (3)
Refer to Section 230-0130, BODY CYLINDER.
There are two single stage, double acting body hoist
cylinders, cushioned at both ends of the stroke, on the
vehicle. The cylinder base end is connected to the
trailer frame and piston rod eye end is connected at
the body. Single stage double acting means that the
piston rod can have oil applied to either end, extending
or retracting the piston rod.
The cushioning effect when the cylinder is being
extended is obtained by a tapered spear on the piston
rod passing through a cushioned sleeve. This
gradually slows the piston which in turn helps to
control destructive shock effects when the piston
reaches the full extent of its travel.
The cushioning effect when the cylinder is being
retracted is obtained by a tapered spear at the base
end of the cylinder body entering a cavity in the piston
rod through a cushioning ring. This gradually slows the
piston which in turn helps to control destructive shock
effects when the piston bottoms.
Cylinder mounting is by pins, spacers and spherical
bearings secured in place by circlips. Spherical
bearings permit a limited amount of cylinder
misalignment.
Pilot Supply Valve (5)
Refer to Section 230-0121, PILOT SUPPLY VALVE.
Mounted to the cradle assembly at the rear of the cab,
the pilot supply valve is a direct acting pressure
reducing valve which steps down the supply pressure
to 30 bar (435 lbf/in²). Intregal of the pilot supply valve
is a relief valve which opens at 45 bar (652 lbf/in²).