H Y D R A U L I C S Y S T E M
S Y S T E M S O P E R A T I O N
R I G H T S I D E O F T R A N S M I S S I ON
1. Hydraulic pump.
11. Pilot relief valve.
The small pump section is the pilot section of the pump.
This section has pilot relief valve (11) in it that keeps the
pilot pressure to a maximum. The pilot oil has two uses. It
goes to the hand metering unit (HMU) of the steering
system to operate the main valve of the steering control
valve. It also goes through a check valve to selector and
pressure control valve (2) for use in the implement
hydraulic system. The selector and pressure control valve
sends the oil onto lift and tilt pilot valve (3). Selector and
pressure control valve (2) also provides pressure oil to lift
and tilt pilot valve (3) to lower the bucket when the engine
is off. The pilot oil does not go through the pilot valve
when the control levers are in the HOLD position. When a
R I G H T S I D E O F C AB
3 . L i f t a n d t i l t p i l o t v a l v e . 1 2 . T i l t d e t e n t l e v e r . 1 3 .
L i f t d e t e n t l e v e r . 1 4 . L i f t k i c k o u t s o l e n o i d . 1 5 . B u c k et
control lever is moved, a valve stem in the pilot
valve lets pilot oil go to lift and tilt control valve
(7). The pilot oil then moves a valve spool in the
lift and tilt control valve which lets oil from the
implement section of oil pump (1) go to either the
lift or tilt cylinders to operate the bucket.
The attachment (third) pilot valve gets its oil
supply from lift and tilt pilot valve (3). The attach-
ment pilot valve operates the same way that the
lift and tilt pilot valve operates.
R I G H T S I D E O F H I T CH
2. Selector and pressure control valve.
The center section of hydraulic pump (1) is the
steering section. This oil is used for the operation
of the steering cylinders to turn the machine.
NOTE: For more information on the steering sys-
tem see, 950B STEERING SYSTEM.
The large section on the drive end of hydraulic
pump (1) is the implement section. It provides the
oil to operate the tilt and lift cylinders. The oil goes
to lift and tilt control valve (7). This valve is an
F R O N T O F L O A D E R F R A ME
4. Tilt cylinder. 6. Lift cylinder (left side). 7. Lift and tilt
control valve. 16. Main relief valve. 17. Head end tilt relief
valve. 18. Rod end tilt relief valve.