Service Manual User Manual

Hydraulic System
9-45
d. Crab Steer
• Left Turn
(Fig. 9– 33)
With the steer select switch in the crab steer position, the
steering control valve spool is shifted so that system
pressure is applied through ports E-C to the intake side
of the steering unit metering section. A specific amount
of hydraulic oil is exhausted from the metering section
and routed back to the control valve section where it is
channeled through ports B-A to the left rod end side of
the front steer cylinder. The steer select valve solenoid is
energized and shifts the valve spool. Oil from the right
side rod end of the front steer cylinder is channeled
through ports P-B of the steer select valve to the right
side rod end of the rear steer cylinder. Oil from the left
side rod end of the rear steer cylinder flows through ports
A-T of the steer select valve to ports D-F in the steering
control valve, then to the reservoir.
Figure 9– 33. Crab steer mode, left turn.
• Right Turn
(Fig. 9– 34)
With the steer select switch in the crab steer position, the
steering control valve spool is shifted so that system
pressure is applied through ports E-B to the intake side
of the steering unit metering section. A specific amount
of hydraulic oil is exhausted from the metering section
and routed back to the control section where it is chan-
neled through ports C-D. The steer select valve solenoid
is energized and shifts the valve spool. Oil is channeled
through ports T-A in the steer select valve then flows to
the left side rod end of the rear steer cylinder. Oil from the
right side rod end of the same cylinder flows through
ports B-P in the steer select valve to the right side rod
end of the front steer cylinder. Return oil from the left side
rod end of the front steer cylinder flows to ports A-F in the
steering control valve and to the reservoir.
Figure 9– 34. Crab steer mode, right turn.
MS0180
a
B
PBG
PB
b
CRAB
STEER
LEFT
PPG
PS
PP
PSG
550
PSI
2500
PSI
A
650
PSI
P
T
T
P
B
A
C
D
E
FEF
SHUTTLE
RESERVOIR
SERVICE
BRAKE
INLET
AUXILIARY FUNCTION MANIFOLD
0.090”
MS0170
PBG
PB
PPG
PS
PP
PSG
550
PSI
2500
PSI
650
PSI
P
T
B
A
C
D
E
FEF
SHUTTLE
RESERVOIR
SERVICE
BRAKE
INLET
AUXILIARY FUNCTION MANIFOLD
0.090”
a
B
b
A
T
P
4-WHEEL
STEER
LEFT
Model 3606 • Origin 10/99