Allmand Brothers Allmand 7.5 FT BACKHOE - Manual (Page 16)

16
REPLACING SECTIONS
For clarification, the inlet cover [cover containing
main relief cartridge (18) ] will be called the left end of
the valve assembly.
Reassemble valve on a flat surface to insure proper
section alignment.
1.
Remove handle assembly from section being
removed.
2. Remove valve from backhoe.
3. Thoroughly clean valve assembly.
4. Before disassembly, mark each section numeri-
cally to avoid incorrect reassembly.
5. Remove four hex nuts and lock washers from
right (outlet cover) end of valve.
6. Slide outlet cover and each section off tie rods.
7. Replace sections as needed. Reassemble valve.
NOTE: Refer to “Replacing Section Seals” if seals
need to be replaced.
WARNING: Do not prelube O-ring
section seals prior to installation.
Compression of lubricants can
distort valve causing spool
binding.
8. Torque stud nuts evenly to 15ft. Lbs .
CAUTION: If stud nuts are not
tightened to proper torque, valve
spools may bind or stick, or cause
O-ring seals to extrude.
9. Reinstall handle assembly. Use locite 242 (blue)
on all screws.
REPLACING SECTION SEALS
1. Disassemble valve as described in previous
section.
2. Remove old O-ring section seals. Be careful not
to scratch or otherwise damage sealing surface
areas.
3. Thoroughly clean O-ring counter bores and
surfaces of each valve section.
4. Place valve assembly on a flat surface for
reassembly.
5. Replace four O-ring seals. Seal Kit contains the
number of section seals required for one work
section/inlet cover.
6. Replace work sections on assembly studs in
reverse order in which they were removed. O-ring
counter bores (with O-rings in place) should be
to your right (downstream side of section) with
inlet cover on your left.
NOTE: Use care when sliding work sections on tie rods
to avoid dislodging O-rings.
1. When all work sections and outlet cover are posi-
tioned on the assembly studs, replace lock washers
and nuts.
2. Torque stud nuts evenly 15ft. Lbs.
SPOOL SEAL REMOVAL
1. Remove handle assembly and clevis pin from spool.
2. Remove bonnet and spool positioner assembly from
rear of the work section.
3. Carefully slide spool out of valve housing.
4. Remove old spool seals. Be careful not to scratch or
damage spool bore and sealing surfaces.
5. Thoroughly clean both seal grooves and exposed end
of spool.
SPOOL SEAL INSTALLATION
1. Lightly oil and insert one new spool seal in handle
end (front) seal groove of valve housing. Verify seal
fit by carefully running your finger around exposed
edge of seal. Seal should have a perfect ridge with no
kinks or twists.
2. Lightly oil valve spool and, starting from positioner
end (rear), reintroduce spool into valve housing.
3. Slowly push spool past seal with a twisting motion.
Stop when seal groove is exposed on positioner end.
CAUTION: Do not pull spool too far, as
this will allow seal in front groove to
enter a spool groove. Seal may be cut
when spool is pushed back.
4. Lightly oil and insert remaining spool seal in bonnet
end seal groove. Verify seal fit by carefully running
your finger around exposed edge of seal. Seal should
have a perfect ridge with no kinks or twists.
5. Return spool to center position with a twisting
motion.
6. Reattach spool positioner. Use loctite 242 (blue)
thread locking compound on spool screw holding
positioner parts to spool. Be careful not to over
torque this screw and twist it off. Use 7 ft. lb. maxi-
mum torque. Slide bonnet in place. Replace bonnet
screws. Torque bonnet screws to 5-7 ft. lbs.
7. Replace spool clevis pin and handle assembly.
VALVE SERVICE