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OMAHA STANDARD
5. Secure the rod so that the piston nut can be removed. Be careful to not mar the chromed
surface of the rod. The rod cannot be repaired if it is dented or scratched. If securing the rod in
a vise, use clean cardboard to pad the vise jaws. Remove the piston nut, piston, spacer tube (if
any) and rod guide.
6. Note the position and orientation of the seals on the piston and rod guide before replacing
them. Be careful to not scratch the seal grooves when removing the old seals. The seals can be
removed with a sharp tool like an awl by carefully pushing the point partially into the seal and
prying the seal from the groove. Hard seals can be removed by carefully cutting the seal apart
with a utility knife or an x-acto knife.
7.Inspect the seal grooves and clean away any contamination. Apply a light coating of clean oil
to the new seals and into the seal grooves to ease installation and prevent scuffing of the
sealing surfaces.
8. Assemble the rod guide and piston onto the rod. Install and tighten the piston nut to the re-
quired torque. For 4” bore cylinders, torque to 625-750 ft.-lbs. For 5” and 6” bore cylinders,
torque to 1175-1400 ft.-lbs.
9. Apply a light coating of clean oil to the piston and guide OD and to the mouth of the
cylinder barrel. Carefully position the piston so that it is centered and square with the cylinder
wall mouth. Once started, push firmly until the piston is about half way down the length of the
cylinder bore. Carefully push the rod guide into the cylinder bore until the front face of clears
the retaining ring groove. Be careful to not mar the chromed rod surface. The rod guide may
have to be driven down the cylinder bore using a hammer and a punch or dowel. Install the
rod-guide retaining ring into the groove and be certain that it is completely nested into the
bottom of the groove. Pull the rod outward until the piston contacts the rod guide. Continue to
pull on the rod until the rod guide is firmly in position against the retaining ring. Install rod
guide retaining capscrews.
10.Check cylinder for external leaks using rated hydraulic pressure. Any leaks should be
evident after the cylinder has been pressurized for one minute. Remove pressure form cylinder.
If the seals are oil tight, the cylinder is ready for service.
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