Remove the O-ring and backup ring from the
outside of the head and the wear rings, buffer seal,
deep Z rod seal, and wiper ring from the inside of the
Do not damage the O-rings during
installation of the holding valve. If the
holding valve turns freely then gets hard
If necessary, remove the holding valve from
to turn, then easy to turn; remove the
the port block.
holding valve and check the O-rings.
They have probably been damaged by a
sharp edge of a port.
Clean all parts with solvent and dry with
compressed air. Inspect all parts for serviceability.
The holding valve should turn by hand
until compression of the O-rings begins.
Before installing new seals and rings,
Carefully install the holding valve into the port
clean all surfaces and carefully remove
block until fully seated.
burrs and nicks.
excessive wear or damage should be
When installing new seals and rings,
avoid stretching seals or scratching the
Stone out minor blemishes and polish with a
grooved or gland surfaces.
fine crocus cloth.
Clean with solvent and dry with compressed
air any parts that have been stoned and polished.
Lubricate new seals and rings with clean
Inspect the barrel carefully for scoring.
Locate the gap of each wear ring 180
degrees with respect to each other.
Steps 1, 2, 3, and 4 are used only if the
Install the wear rings into the head.
holding valve has been removed.
Check the inside of the port block for any
sharp edges or burrs and remove as necessary with
Improper installation of seals could
cause faulty cylinder operation.
Install new O-rings onto the holding valve, refer
Install the buffer seal, deep Z seal, and wiper
to Figure 2-8-26.
ring inside the head ensuring the seals are
assembled properly and installed in the correct
Lubricate the holding valve and O-rings with
clean hydraulic oil.