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4
PILOT VALVE
DISASSEMBLY AND ASSEMBLY
Inspection and adjustment
Checking the parts
Part Criteria Action
O-ring — •
Replace
Seal — •
Replace
Spool •
Wear on the sliding portions is 10 μm or greater com-
pared to the non-sliding portions.
• Scratches on the sliding portions
• Spool does not move smoothly
• Replace
• Replace
• Replace
Push rod • Front end is worn 1 mm or more
• Scratches on the sliding portions
• Replace
• Replace
Plug •
Seal is imperfect due to damage • Repair or replace
Controls • Tightening is loose at the pin, shaft or joint of the con-
tr
ols, with looseness of 2 mm or greater
• Due to wear, etc., tightening is loose at the pin, shaft or
joint of the controls, with looseness of 2 mm or greater
• Tighten to the specified torque
• Replace
Casing, port plate •
Scratches, rust, or corrosion at the sliding parts with the
spool
•
Scratches, rust, or corrosion of the seal part in contact
with the O-ring
•
Replace
• Repair or replace
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