General maintenance – Autoquip DOUBLE PANTOGRAPH LIFT User Manual
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' PH '
CYLINDER REPACKING (Reference Figure 6)
1.
Remove the cylinder as described above in Cylinder Removal.
2.
Pull the rod out of the cylinder tube sufficiently to gain access to the 'spanner
wrench holes’ on the rod end of the cylinder. Do not allow oil or dirt to be pulled
back into the hydraulic hose.
3.
Insert a Spanner wrench in the upper bearing assembly and turn the bearing
assembly counter clockwise until the tip of the retainer ring appears in the slot
located on the cylinder outer casing.
4.
Insert a small blade screwdriver under the tip of the retainer ring and turn the upper
bearing assembly counter-clockwise until the retainer is removed from the slot.
NOTE: The wire retainer ring may be a cutting or puncturing hazard.
5.
Pull the rod out of the tube slowly to remove the rod and bearing assembly.
NOTE: Use caution to prevent surface damage to the rod. This could result
in seal failure and/or leakage.
6.
After all the internal components have been removed, use a bright light to inspect
the inner walls of the cylinder barrel. Use a cylinder hone if necessary to remove
any apparent nicks or scratches. Clean and flush the barrel thoroughly after honing
to remove chips and grit.
7.
Remove the piston lock nut and slide off the piston and bearing assembly.
Take care to protect the rod surface from damage. The upper trunnion clevis and
pin on the Leg assembly may be used secure the cylinder rod and prevent rotation
of the rod while loosening the piston lock nut.
8.
Inspect all piston grooves and seal surfaces for any imperfections and repair or
replace as necessary. Install new packing and seals on the piston, rod, and bearing
assembly. See Figure 19.
9.
Liberally lubricate the piston and seals with CLEAN grease or oil. Install the seal
and piston on the rod assembly. Install the Rod Lock Nut on the rod and torque the
Lock Nut to: 325 ft. lbs. on 3.0" Bore, 3.5" Bore & 4" Bore cylinders. On 5"
Bore Cylinders, torque the Rod Lock Nut to 350 ft. lbs. The upper trunnion clevis
and pin on the Leg assembly may be used to prevent the rotation of the rod while
tightening.
10.
Again, liberally lubricate the piston and seals with CLEAN grease or oil and install
the rod and piston into the cylinder casing tube using care not to damage any seals
or packing.
GENERAL MAINTENANCE