TM 5-3895-346-14
HYDROSTATIC SYSTEM
TROUBLESHOOTING
CAUSE
INDICATED BY
REMEDY
B.
Control valve out
1. Replace displacement con-
of adjustment
trol valve or readjust ac-
cording to the following
procedure:
STEP I: (Refer to Fig. 3.)
Remove end play from center-
ing-spring mechanism with
locknut (1) loose but holding
the centering-spring housing
(3). Turn the spring adjust-
ing screw (2) until the screw
is just touching the center-
ing-spring washer; thus taking
the free end play out of the
centering-spring mechanism.
This is best done by exerting
a light back and forth force
on the control-valve spool (6)
at the same time the adjusting
screw is being turned down.
Care must be taken not to com-
press the centering-spring (4)
beyond its installed height.
Tighten the locknuts (1) and
recheck the spool (6) for end
play.
STEP II: (Refer to Fig. 3.)
Adjust control valve spool for
neutral position. Remove the
7/16 x 20 straight thread O-
ring plugs on either side of
the control valve housing (9)
to reveal the servo cylinder
porting holes (8). Loosen
locknut (7) and adjust the
control valve by screwing the
centering-spring housing (3)
in or out so that the open
areas (shaded areas of (10))
between the spools lands and
sides of the porting holes are
equal. Tighten locknut (7),
recheck the open areas and re-
install the two 7/16 x 20
plugs.
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