(1) Remove ball stud used on the control valve end of
the cylinder by removing the dust cover, and split collar
(1) Discard all sealing elements and scrapers and
clamping bolt on the ball stud housing, and unscrewing
replace with new, upon reassembly. Wash all parts in a
the ball stud from the housing.
good grade of mineral spirits.
(2) Loosen and remove the four capscrews that secure
(2) Inspect all fluid passages in valve body and
the control ball stud housing and valve assembly to the
cylinder to be certain they are clean and free from
cylinder. Remove the control ball stud housing and valve
assembly from the cylinder. Remove three packings
from recesses in the body.
(3) Check each disassembled part for excessive
wear, cracks, or pitting that would render them unfit for
continued use. Replace all defective parts.
Care must be taken not to score or
(4) Inspect valve spool for. deep scoring and
otherwise damage the cylinder or valve
excessive wear. Check valve spool bore for similar
scoring or pitting. Replace these parts if badly damaged
or worn. Do not rework or attempt to "touch-up" the
(3) Hold control ball stud housing and valve assembly in
valve spool. This practice will only result in improper
a vise, by lightly clamping valve body. Use care not to
steering unit operation and performance.
distort spool bore in valve body. Remove the wire ring
which locks the control ball stud sleeve plug and remove
(5) Inspect cylinder shaft for
plug. Remove control ball stud, two ball stud seats,
straightness to insure proper sealing.
spring washer and spacer.
e. Control valve assembly.
(4) Remove self-locking nut from capscrew. Remove
capscrew, washer and control ball stud sleeve. Then lift
the two centering spring retaining washers, centering
Immerse all parts in clean hydraulic fluid to
spring and spacer from the valve body. Remove control
facilitate reassembly. Refer to Figure 6-13
spool from the control ball stud end of body. Remove
and proceed with reassembly. Be sure that
packing from valve body and from spool to complete
all oil seals, wipers, and packing are
discarded and replaced with new parts for
reassembly. Remember that a seal can only
do its job when properly seated to prevent
fluid leakage and entrance of air into the
The check valve retaining plug with integral
system. Coat all seals with liberal amounts
valve body-cylinder locating pin should be
of GAA or petroleum jelly prior to assembly.
removed for inspection.
(1) Install new packing (coated with grease or
c. Cylinder disassembly. The cylinder assembly is a
petroleum jelly) in cylinder end of valve body and on
sealed unit. Overhaul procedures are restricted to
control ball stud end of valve spool. Install spool in bore
replacing the sealing parts on the rod end.
from the control ball stud end to avoid packing
interference during assembly.
(1) Remove anchor ball stud by removing nut, bolt,
and lockwasher from the ball stud housing and
(2) Install washer, spacer, centering spring, washer,
unscrewing the ball stud.
control ball stud sleeve, capscrew washer and capscrew.
Install self-locking nut and tighten until play between
(2) Remove retainer snap ring with snap ring pliers.
parts is removed. Be sure that nut is in good condition
Rotate the rod and withdraw it far enough from the
and that the centering spring remains aligned between
cylinder to expose scraper, wiper ring, retainer and
the two remaining washers. Back nut off one flat (1/6
washer. The shaft seal assembly may be removed with
turn or 60 degrees).
a hooked scriber.
(3) Start control ball stud sleeve plug in control ball
(3) Steel seat ball stud assemblies used can be
disassembled for inspection. First remove the cotter
pin,, plug, spring and outside seat. Then remove the ball
(4) Slide the control ball stud housing over the ball
stud nut, spring, shield and dust cover. Remove the ball
stud, the other seat and the grease fitting.
(5) Install the studs which attach the valve to the
cylinder, if they were removed.