SkyTrak 8042 Service Manual - Manual (Page 480)

8.65 Model 8042, 10042, 10054 Legacy Rev. 10/03
Hydraulic System
b. Four-Wheel Steering
When the steer select switch (5) is in the four-
wheel steer (rear) position (6), the front wheels
(7) will steer in the direction the steering wheel is
turned and the rear wheels (8) will steer in the
opposite direction.
1. Four-Wheel Steering Left Turn
(refer to page 8.50)
With the steer select switch (5) in the four-wheel steer
(rear) position (6), one of the steer select valve solenoids
is energized. The power steering unit control valve spool
is shifted so that the system pressure from the secondary
function valve is applied to the intake side of the power
steering unit metering section.
A specific amount of hydraulic oil is exhausted from the
metering section and routed back to the power steering
control valve section, internal to the power steering unit,
where it is channeled to the left rod end of the front
steering cylinder.
Oil from the right rod end of the front steering cylinder
flows through the steer select valve to the left rod end of
the rear steering cylinder. Oil from the right rod end of the
rear steering cylinder flows through the steer select valve
and back to the power steering control valve, then to the
return filter in the reservoir.
2. Four-Wheel Steering Right Turn
(refer to page 8.52)
With the steer select switch (5) in the four-wheel steer
(rear) position (6), one of the steer select valve solenoids
is energized. The power steering unit control valve spool
is shifted so that the system pressure from the secondary
function manifold is applied to the intake side of the power
steering unit metering section.
A specific amount of hydraulic oil is exhausted from the
metering section and routed back to the power steering
control valve, internal to the power steering unit, where it
is channeled through the steer select valve to the right rod
end of the rear steering cylinder.
Oil from the left rod end of the rear steering cylinder flows
through the steer select valve to the right rod end of the
front steering cylinder. Oil from the left rod end of the front
steering cylinder flows back to the power steering control
valve, then to the return filter in the reservoir.
MA7020
5
6
7
8
5
MT3880