7
EATON Char-Lynn
Power Steering Control Unit Series 5 Parts and Repair C-STCU-TS002-E1 November 2006
Reassembly
Check all mating surfaces.
Replace any parts with scratch-
es or burrs that could cause
leakage. Wash all metal parts in
clean solvent. Blow them dry
with pressurized air. Do not
wipe parts dry with paper tow-
els or cloth as lint in a hydraulic
system will cause damage.
Note:
Always use new
seals when reassembling
hydraulic steering control units.
Refer to page 5 for seal kit
part numbers.
Important:
During reassembly
lubricate the new seals with
a petroleum jelly such as
Vaseline
®
. Also lubricate
machined surfaces and bearings
with clean hydraulic fluid.
10. Install the quad seal
(see page 12 for 2-piece
seal installations):
• Put one of the bearing
races and sleeve into
the housing.
• Together, the housing and
bearing race create a groove
into which the
quad seal will be installed.
• Hold the bearing race tightly
against the input end of the
housing by pushing on the
gerotor end of the sleeve.
• Fit the quad seal into its seat
through the input end of the
housing. Be sure
the seal is not twisted.
• Remove the sleeve and
bearing race.
11. Lubricate and install the dust
seal (see Figure 4 for correct
seal orientation).
12. Install the centering springs
in the spool. It is best to
install the two flat pieces
first. Next, install the curved
pieces, three
at a time.
13. Fit the retaining ring over
the centering springs.
14. Apply a light coating of
clean hydraulic fluid to
the spool and slide it into
the sleeve. Be sure the cen-
tering springs fit into the
notches in the sleeve.
15. Install the drive, be sure the
slot in the drive engages
the pin.
16. Install the pin
(see Figure 3).
17. Apply a light coating of
petroleum jelly to the
inner edge of the dust
and quad seals.
18. Put the thrust bearing and
races into the housing.
The thrust bearing goes
between the two races
(see Figure 2).
19. Apply a light coating of
clean hydraulic fluid to
the spool and sleeve assem-
bly and slide it
into the housing.
Important:
Do not damage
the dust or quad seals..
20. Clamp the housing in a vise
as shown in Figure 5. Use
just enough clamping force
to hold the housing secure-
ly.
21. Lubricate and install a new
o-ring seal in the groove in
the housing.
22. Install the wear plate and
align the holes in the wear
plate with threaded holes in
the housing.
Note:
The holes in
the wear plate are
symmetrical.
23. Lubricate and install a new
o-ring seal in the groove in
the wear plate.
24. Install the gerotor and align
the screw holes.
25. Lubricate and install a new
o-ring seal in the groove in
the gerotor ring.
26. Lubricate and install a new
o-ring and seal ring in the
groove in the gerotor star.
27. Install end cap and seven
cap screws. Tighten cap
screws, in a crisscross pat-
tern, to 16 -18 Nm
[140 -160 lb-in].
28. Remove the SCU from
the vise.
29. Install the relief valve/check
or check ball and plug. Use
a new o-ring and tighten the
plug to 17 Nm [150 lb-in].
Quad Seal
Dust Seal
Thrust Bearing
and Race (2)
Round and
Square Housing
with Side Ports -
Reassembly
Figure 4
Figure 5
Standard Torque
Centering Springs
and Spacers
Sleeve
Pin
Spool
Spring
Retaining
Ring
Low Torque
Centering Springs
and Spacers
Figure 3
