Bush Hog CBH80 - Manual (Page 27)

MODEL CBH 60 MONOBLOCK
VALVE REPAIR - DISASSEMBLY
Replacing Spools Seals:
Note: For the purpose of these instructions we will
consider the control handle side of the valve as the
FRONT, and the opposite side as the BACK.
1. Remove control valve from the backhoe.
2. Throughly clean the exterior of the valve before
beginning disassembly procedures.
3. At the BACK of the valve remove all bonnet
assembly parts which are connected to the spool.
Keep parts in the order of disassembly. See each
valve section parts breakdown for the parts involved
in the make-up of the bennet assembly.
IMPORTANT: DO NOT remove the spool from
the valve. The seals can be replaced externally.
Prevent spools from turning or moving by
inserting a screw drive through the clevis slot,
or by running a rod through the pin hole and
using the rod as a handle.
DO NOT hold the spool with a wrench. This will
destroy the finish.
4. At the BACK of the valve, remove seal retainer,
back-up washer, and spool O-ring seal, or retaining
sleeve, bonnet O-ring seal and spool O-ring.
5. Throughly clean counter bores.
6. Install new seals:
A. Spring-Centered Bonnet Assembly Only:
Lightly oil new O-ring seal. Slide seal over valve
spool and insert weal in counter bore. Replace back-
up washer and seal retainer.
B. Float Bonnet Assembly Only:
Lightly oil new O-rings. Install O-rings into spacer.
Slide spacer with O-rings over valve spool being
careful to orient as shown in boom valve section
breakdown.
7. At the BACK of the valve replace bonnet assem-
bly parts, reversing the order in which they were dis-
assembled in step 3. Use 6 - 8 ft. lbs. Torque to
tighten assembly screw on spring centered bonnet
assembly.
8. At the FRONT of the valve remove all parts con-
nected to the spool (handle, linkage, etc.).
9. At the FRONT of the valve remove seal plate
retainer, back-up washer and spool O-ring seal.
10. Throughly clean counter bore.
11. Lightly oil new O-ring seal. Slide O-ring seal over
valve spool and insert in seal counter bore. Replace
back-up washer and seal plate retainer.
12. Reattach all parts connected to the spool (han-
dle, linkage, etc.)
25
FRONT
MODEL CBH 60
MONOBLOCK VALVE
Bonnet
Assembly
Seal Plate Back Up Washer
“O”- Ring
Float
Bonnet
Assembly
Figure 11