EATON
WCB11076.1 WCBD Brake Assemblies with ORB Coolant Ports Installation, Operation and Maintenance Manual October 2014
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4.0 MAINTENANCE
Note: Refer to WCB2 tensioner/brake manual WCB 11076 for
maintenance of the WCBD brake assembly, with the exception
of section 4.1, which covers cylinder seal replacement.
The WCBD brake assembly cylinder seal replacement is
covered in this manual.
4.1
Dual Cylinder Seal Replacement
4.1.1 Disconnect the air connections
4.1.2 While supporting the cylinder, loosen the
locknuts (18) ONE TURN AT A 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.
4.1.3 Using lifting equipment, carefully remove the
cylinder (19) and piston (33) as an assembly.
Set aside in a clean area.
4.1.4 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.
4.1.5 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 any of the pressure
ports on the cylinder.
Caution
Application of a higher pressure may cause damage
to the components.
4.1.6 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 or small brass drift 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.
4.1.7 Remove the seals. Note how the lips of the
Inner (21), Outer (23), and Intermediate (114) seals
are oriented. Refer to Figure 1
Note: Upon disassembly and inspection, a one-piece seal may be
found for all intermediate seals (114) and on the inner (21) and
outer (23) seals. These seals have since been superseded with
two seals being installed ‘back-to-back’ as shown in Figure 1.
4.1.8 Inspect the cylinder sealing surface condition for
nicks or scratches, corrosion, or any other defect
which may prevent the seals from being effective.
The maximum amount of radial wear on the seal
surfaces is 0.005" (0,13 mm). The wear on the sealing
surfaces will be in the form of grooves where the
seals contact the cylinder wall. Replace the cylinder,
if necessary.
4.1.9 Thoroughly clean the seal grooves in the piston (33)
and apply a thin coat of Molykote
®
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), and (114).
4.1.10 Install the new seals in the grooves in the piston,
noting the orientation of the seal lips. See Figure 1.
4.1.11 Position the cylinder on a flat level surface so that the
pressure cavity faces upward.
4.1.12 Carefully place the piston onto the cylinder with the
chamfered edge of the piston facing downward,
taking special care to avoid damaging the seal lips.
4.1.13 Gradually apply an evenly distributed force to
press the piston into the cylinder being sure not
to cock the piston, which may damage the sealing
surfaces. The use of ’C-Clamps’ may assist with the
assembly process.
4.1.14 Using a lifting strap, slide the cylinder/piston
assembly onto the studs.
WCBD Brake Assemblies with ORB Coolant Ports
