
6-23
Part name
Inspection item
Criteria & measure
Â
Existence of scratch, rusting or corrosion.
Â
Existence of scratch, gnawing, rusting or
corrosion.
Â
O-ring seal sections at both ends.
Â
Insert spool in casing hole, rotate and
reciprocate it.
Â
Damage of poppet or spring
Â
Insert poppet into casing and function it.
Â
Rusting, corrosion, deformation or breaking
of spring, spring seat, plug or cover.
Â
External oil leakage.
Â
Rusting, corrosion or deformation of seal
plate.
Â
External rusting or damage.
Â
Contacting face of valve seat.
Â
Contacting face of poppet.
Â
Abnormal spring.
Â
O-rings, back up rings and seals.
Â
In case of damage in following section,
replace part.
- Sliding sections of casing fore and spool,
especially land sections applied with
holded pressure.
- Seal pocket section where spool is inserted.
- Seal section of port where O-ring contacts.
- Seal section of each relief valve for main,
travel, and port.
- Other damages that may damage normal
functions.
Â
Replacement when its outside sliding
section has scratch(Especially on seals-
contacting section).
Â
Replacement when its sliding section has
scratch.
Â
Correction or replacement when O-ring is
damaged or when spool does not move
smoothly.
Â
Correction or replacement when sealing is
incomplete.
Â
Normal when it can function lightly without
being caught.
Â
Replacement for significant damage.
Â
Correction or replacement.
Â
Correction or replacement.
Â
Replacement.
Â
Replacement when damaged.
Â
Replacement when damaged.
Â
Replacement.
Â
100
replacement in general.
Block
Spool
Poppet
Around spring
Around seal
for spool
Main relief valve &
port relief valve
2
2
. MAIN CONTROL VALVE