10.13.14 Steer Select Valve - JLG sky trak mmv Service Manual

10.13.14 Steer Select Valve

The steer select valve (19), is secured to the steer select
manifold and frame with four capscrews (20) and
o-rings (21) near the hydraulic fluid reservoir.
It contains two solenoids that direct hydraulic fluid
through hoses and ultimately help operate the steering.
The valve is a direct dual-solenoid operated, spool-type
directional control valve. The steer select valve controls
the start, stop and direction of hydraulic fluid flow to the
steering cylinders mounted on each axle. The valve con-
sists of a housing (22), two solenoids (23), a control
spool (24), and two return springs (25).
In the de-energized state, the spool (24) is held by the re-
turn springs (25) in the center position. The spool is shift-
ed through the action of the two wet-pin type
solenoids (23).
The force of an acting solenoid works against the push
pin (26) on the end of the spool (24). The spool is shifted
from its normal position to the end position for selected
flow. The selected flow pattern is covered in Section 9,
Hydraulic System .
19
Model MMV Rev. 12/04
20
MT1400
21
25
23
26
When the solenoid is de-energized, the control spool (24)
is returned to its normal condition by the centering
springs (25).
Check the steer select valve solenoids for proper opera-
tion and check the wiring for continuity or shorts. When
energized/de-energized, the solenoid should move
and/or an audible "click" should be heard; check for the
presence of voltage with a voltmeter. Replace a defective
or faulty steer select valve with a new unit. (Refer to
Section 10.7.14, Front Steer Circuit and Troubleshooting
subsequent circuits and troubleshooting charts.)
Electrical System
19
22
23
26
25
24
MT1480
10.161