NOTE: Be sure to mark an index point on the case and spool to insure proper
reassembly.
INSPECTION AND SEAL REPLACEMENT
1. The “case” bore should be thoroughly washed with solvent or diesel fuel and
inspected for signs of “scoring” or deep scratches. This type of damage is
generally caused by the presence of foreign material in the hydraulic system.
No satisfactory method of repairing this type of damage can be conducted in
the field.
2. The “spool” should be carefully washed in solvent or diesel fuel. The seals and
“O” rings should not be removed from the spool unless they show signs of
wear or damage. NOTE: If the seal is removed for any reason, it should be
replaced since removal will almost always damage it beyond use
When installing a new seal and ring, it must be “walked” into place past other seals and oil
grooves and then into its own groove in the same manner that the bead of a tire is “walked”
into the wheel rim. The spool should be well oiled to aid in this assembly. Best results can
be achieved if the spool, with the seals mounted on the end, is allowed to sit overnight.
This gives the seals a chance to adjust to normal size.
REASSEMBLY
1. The top and bottom “O” rings and back-up washers can be replaced without
removing the spool. Removing the top cover exposes the top “O” ring. The
spool will drop out of the case, exposing the bottom “O” ring.
UPON REASSEMBLY, INSTALL THE UPPER “O” RING AND BACK-UP
RING AFTER THE SPOOL IS IN THE CASE. THIS WILL PREVENT ANY
DAMAGE WHICH MIGHT RESULT FROM SLIDING PAST PORT OPENINGS.
2. The rotary manifold should be reassembled using a generous coat of oil on the
case ID and spool OD. Generally, reassembly is most successful by placing the
case in a vertical position and inserting the spool into the case. Each seal and
wear ring should be compressed by hand to initially enter the case bore. With
the spool fully inserted into the case, the assembly may be “up-ended” to
replace the end plate.
3. Ports should be properly protected, capped, and, preferably, oil filled without
pressure.
NOTE: If the rotary manifold is oil filled and plugged, ample air space should be
allowed for the expansion of oil due to temperature changes.
251REVISED:
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