Ross CDA-10 Installation, Maintenance And Operating Manual Download Page 14

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HYDRAULIC LIFT PACKING.

1. The chevron style main packing consists of seven (7) layers: one (1) split top binder, one (1) split chevron oil seal
layer, four (4) continuous individual chevron oil seals and one (1) split bottom binder.

2. Chevron packing is of the non-compression and self-adjusting type. Oil pressure against the inverted “v” forces
the packing to spread, sealing it against the piston and the inside of the cylinder wall.

3. To replace the Chevron packing:

a. Raise the machine to a convenient working height and support the drive bonnet using an appropriate
supporting system. This support system must be capable of holding the drive bonnets weight.
b. When the drive bonnet is securely supported, loosen the bolts that hold the drive bonnet to the hydraulic
cylinder and lower the cylinder from the drive bonnet.
c. If the cylinder fails to lower, the packing may be too tight and will need to be loosened.
d. After the cylinder has been completely lowered, release all pressure from the air/oil system and

disconnect the air pressure line from the oil reservoir.

e. Remove all of the screws from the packing gland located on the top of the cylinder and remove the
packing gland with the wiper ring attached.
f. Check the condition of the wiper ring visually. If it looks to be in good condition, invert the packing gland/
wiper ring assembly and slip it over the cylinder and slide it up and down. If the wiper appears to have a
sloppy fit, shows signs of wear or damage or is hard to fit, it should be replaced.
g. If the wiper needs to be replaced:

1. Pull out the old wiper and thoroughly clean the groove.
2. Gently tap the new wiper into the groove with a fiber hammer, a lap joint will result.
3. Pull out both ends of the joint, fit the ends together and reinsert into the groove.
4. A loop will appear on each side of the inlet.
5. Work out loops by tapping outward in each direction from the fitted joint. Continue until the
loops disappear.
6. NOTE: You must begin the composition wiper split joint 180 degrees (opposite) from the grease
fitting.
7. To ensure a smooth fit, invert the packing gland with the new wiper and fit it over the cylinder.
Tap the gland ring with a fiber hammer to smooth the wiper surface.

h. Remove the old packing using a packing puller one layer at a time until the bronze guide ring is exposed.
i. Thoroughly clean the packing box.
j. Coat all of the new packing rings with a film of hydraulic oil.
k. Begin to install the new packing by inserting the split bottom starter ring into the bottom of the packing
box and on top of the bronze bushing.
l. Use an appropriate tool to feather the edges of the chevron packing into the packing box and around the
cylinder.
m. Continue to replace the new packing pieces row by row until all rows are in place.
n. When installing split packing rings, rotate the split position to prevent the splits from lining up with each
other.
o. Install the packing gland/wiper assembly and bolt into position.
p. Lubricate the seals using a medium chassis grease.
q. Pressurize the system, bleed the air from the cylinder, raise the cylinder up to the bonnet and bolt the
cylinder to the bonnet.
r. Raise the cylinder and bonnet slightly off the supports and check for leaks. Tighten the packing as

required.

s. Remove the supports and operate the lift up and down several times.