Paccar CARCO 50B, Service Manual

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40
CLUTCH ASSEMBLY SERVICE
NOTE: In April of 2001 Carco began using a new
slotted housing clutch assembly in all 50B/70A
winches (Serial Number 0100513 and higher).
Basic service instructions are unchanged from the
splined housing clutch assembly. New friction
discs are used in both the clutch and brake and
are interchangeable with old discs, however, new
and old discs should not be mixed in the same
assembly. A complete slotted brake assembly can
replace a splined assembly. See Carco Service
Bulletin LIT2041 for additional information.
Two identical clutch assemblies are mounted on the
clutch shaft: One is used to Reel-In, the other for Reel-
Out. Each clutch contains five friction discs (12) splined to
the bevel gears and four steel discs (13) splined to the
clutch housing. The clutch housing is splined to the clutch
shaft.
When the operator shifts his control handle to operate the
winch, hydraulic pressure is directed through a passage
in the clutch shaft to the appropriate clutch housing. The
oil pressure then acts on the clutch piston to compress
the steel and friction discs thereby locking the bevel gear
to the clutch shaft and winch gear train.
When the operator returns the controls to “Brake-on”, the
clutch application oil will be exhausted through the control
valve and through a small check valve installed in the
clutch housing. The piston return springs (3) will push the
piston away from the clutch discs and permit the bevel
gear to turn free of the clutch shaft which is now locked
by the spring applied brake.
REMOVAL
Right hand or left hand clutch removal may be accom-
plished with a winch mounted to the tractor. However, if
both clutch assemblies are to be inspected for repair
and/or replacement, it is advantageous to remove the
winch from the tractor.
The bevel pinion carrier and pump assembly is removed
from the front of the winch and, after removal of the brake
assembly, the complete clutch and bevel gear shaft
assembly is removed through the brake opening on the
right hand side of the winch.
Refer to Clutch Shaft Group, for removal and disassem-
bly of the clutch and bevel gear shaft assembly.
DISASSEMBLY
Remove the pressure plate retaining ring(s) (7) using
slight pressure to compress the wave springs, if so
equipped.
Remove the pressure plate (10), clutch friction discs (12),
steel discs (13), and the wave springs (18) as required.
Inspect friction discs for wear and flatness. Original disc
thickness is .138-.148 in. (3.5-3.8 mm). Oil groove depth
on new discs is .015 in. (.38 mm) minimum. Replace fric-
tion discs if the oil groove is .005 in. (.13 mm) or less, disc
is not flat, or friction material is worn unevenly.
Inspect steel discs for scoring and warpage. 50B/70A
discs are flat and .093 in. (2.36 mm) thick. Replace steel
discs if they are not flat beyond .015 in. (.4 mm), heat dis-
colored, or show signs of friction material transfer.
i
ITEM DESCRIPTION QTY.
1 Plug, O-Ring Flush 2
2 Steel Check Ball 1
3 Spring 8
4 O-Ring 1
5 O-Ring 1
6 Retaining Ring 1
7 Retaining Ring 2
8 Spring Retainer 1
9 Check Valve Seat 1
10 Pressure Plate 1
11 Clutch Housing 1
ITEM DESCRIPTION QTY.
12 Disc, Friction, Bronze 5
13 Disc, Steel 4*
14 Clutch Piston 1
15 O-Ring 2
16 Pin 1
Splined
Clutch
Assembly