Failure to machine wear plates flat
could result in poor contact between
the friction couple and subsequent
reduction or erratic torque of the
tensioner.
After replacement or machining of wear
plates, a minimum wear-in period of four
hours at 50% of the rated horsepower
is recommended for the friction couple
to achieve rated torque.
4.7
Cylinder Seal Replacement
Note: Item numbers (#) are shown on
Figures 1 and 2.
4.7.1
Disconnect the air connections.
4.7.2
While supporting the cylinder, loosen the
locknuts (18) ONE TURN AT TIME and in an
alternating (crosswise) pattern until the spring
force is completely relieved. Remove the
locknuts and washers (17). Deep well sockets
are required for removal of the locknuts.
4.7.3
Using lifting equipment, carefully remove the
cylinder (19) and piston (33) as an assembly.
Set aside in a clean area.
4.7.4
Place the cylinder and piston assembly
with the piston facing down on blocks
approximately 6" (150 mm) high. The blocks
must only contact the cylinder (19) so that
the piston (33) will be free to move out of
the cylinder bore.
4.7.5
If a regulated air line is available, the piston
can be partially ejected from the cylinder by
applying no more than 15 PSIG (1.0 bar)
to the cylinder.
Application of a higher pressure may
cause damage to the components.
4.7.6
To complete the removal of the piston from the
cylinder, open all air inlets. Alternately insert a
0.50" (12 mm) diameter by 6" (150 mm) long
wood dowel into each air inlet and gently tap the
piston with a mallet so that it moves evenly out
of the cylinder. Be careful not to damage the
sealing surfaces of the piston or cylinder by
cocking the piston in the cylinder.
4.7.8
Noting how the lips of the seals are oriented
in the piston grooves, remove the seals.
4.7.9
Inspect the cylinder sealing surface condition
for nicks or scratches or any other defect which
may prevent the seals from being effective. See
Table 14 for wear limits of the sealing surface.
Replace the cylinder, if necessary.
4.7.10
Thoroughly clean the seal grooves in the
piston (#) and apply a thin, even coat of Dow
Corning
®
55 O-ring lubricant to the piston seal
grooves and chamfer on the piston, the sealing
surfaces in the cylinder (19), and the seals
(21)(23).
4.7.11
Install the new seals in the grooves in the
piston, noting the orientation of the seal lips.
See Figure 19.
4.7.12
Position the cylinder on a flat level surface so
that the pressure cavity faces upward.
Figure 18
WCB 11070 VP 4.2 Format
23
© Copyright Eaton Corp., 2003. All rights reserved
April 2002 (Revised June 2003)
