Southworth APCU Series, Operating And Maintenance Manual

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36 APCU Owner’s Manual
CAUTION!
During reassembly, it is very important to
keep all of the parts free of dirt, dust, metal
chips, water, and other contamination. Most
of the problems with hydraulic systems are
caused by contamination in the oil.
7.
Clean all of the surfaces on the gland. Install a new
quad ring and BU washer. Install a new wiper ring
in the correct orientation. Coat the inner diameter
of the gland with light grease and replace it on the
rod.
CAUTION!
Be careful not to install the wiper back-
wards.
8. Clean the piston surfaces. Install a new larger O-
ring and leather BU washer on the piston. Install
a new piston ring. Install a new smaller O-ring.
Attach the piston to the rod and tighten the large
nut.
9. Clean the bore of the cylinder tube thoroughly. In-
spect the bore of the tube for scratches which run
up and down, along the length of the cylinder. If
you do see any scratches, hone the inner surface of
the cylinder. Be sure to clean the tube thoroughly
after you do this.
10. Lubricate the inner diameter of the cylinder tube
with a light coating of hydraulic oil. Carefully insert
the piston and rod back into the cylinder. Be very
careful not to damage the piston ring, O-ring or BU
washer as you do this. It may be helpful to tip the
rod assembly and twist it as you slide it into the
cylinder. Once the piston is inside the cylinder, it
should slide easily.
11. Slide the gland assembly into the cylinder. Rotate
the gland so the port lines up with the hole in the
cylinder tube. Install a new snap ring. Compress
the snap ring, tap the gland into place, then relax
the snap ring. Be sure that the snap ring is in place
in the groove.
12. Install the cylinder in the unit as described below.
Replacing a Cylinder
Before beginning this procedure, please read and un-
derstand this entire section.
1. Before beginning, read steps 2 through 4 in the
procedure “Removing a Cylinder” listed above.
2. Place the cylinder near the point where it will fit
into the mechanism. Be sure the cylinder ports are
oriented correctly.
3. Align the lower cylinder with each lower cylinder
clevis and insert the lower cylinder clevis pin. Be
careful! The cylinder is heavy! Replace the “keeper”
and secure it with the button-head cap screws (sup-
plied). Repeat the same procedure to replace and
secure the clevis pin for the upper cylinder.
4. Attach the lower and upper hydraulic supply lines.
5. Be sure everyone is clear of the equipment. Turn
on the power and test the unit. Run the mechanism
through a couple of cycles to completely purge any
air trapped in the hydraulic lines.