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 five steel discs (13) with tangs to engage the slotted 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 accomplished 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 side of the winch.
Refer to Clutch Shaft Group, for removal and disassembly 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 friction 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, PA55/PA56 discs are flat and .093 in. (2.36 mm) thick. Replace steel discs if they are not flat beyond .015 in. (.4 mm), heat discolored, or show signs of friction material transfer.
Using a suitable press or two C-clamps, depress spring retainer (8) and remove retaining ring (6) and clutch spring retainer (8).
Remove the eight clutch piston return springs (3). During the rebuild of clutch assemblies, it is recommended to replace all eight springs. Minimum spring free length is 1.16 in. (29.5 mm) for springs in slotted housings.
Turn the clutch housing over and tap on bench top to remove clutch piston (14). Remove two plugs (1) to aid in piston removal. Inspect piston for wear or damage.
Remove O-rings and back-up rings from the piston. Replace O-rings and/or back-up rings upon reassembly.
Remove the check valve seat (9) and steel ball (2) from the back side of clutch housing (11). Inspect for wear and make sure all foreign material that may restrict the steel ball seating action is removed.
Remove the two flush plugs (1) from the back side of the clutch housing.
Assembly
Thoroughly clean and inspect all components prior to assembly.
Install the steel check-ball (2) into the back side of clutch housing (11). Lightly coat threads of check valve seat (9) with Loc-tite 242 and install flush with the surface of the clutch housing. Make certain that the steel ball moves freely and no thread locking compound is in seat area.
Install back-up rings (16 & 17) into grooves in clutch piston. Lubricate O-rings (4 & 5) with hydraulic oil and install them in the grooves with the back-up rings.
NOTE: The concave (cupped) side of the back-up ring MUST always face the O-ring. Back-up rings are toward the side of the piston that pushes against the clutch discs, as shown.
Lubricate the piston O-ring sealing surface with hydraulic oil then push piston (14) into bottom of clutch housing (11). Install spring retainer (8) over springs.
Using a suitable press against spring retainer (8) compress springs to expose the retaining ring groove. Install retaining ring (6) with the sharp edge of the inner diameter of the retaining ring facing away from the clutch springs.
NOTE: Pre-lubricate the clutch discs in winch lubricant before assembly.
Install the two flush plugs (1) into the back side of the clutch housing.
Install the discs by starting with a steel separator disc (13) (lugs on outside diameter) next to the piston and alternate with a friction disc (12) (teeth on inside diameter) until a total of five friction discs and five steel discs and have been installed. Install a wave spring (18) between each set of friction discs centered around the steel plates.
Install the pressure plate (10) and retaining ring (7).
Clutch Assembly
The assembled clutch must have .090-.140 in (2.3-3.6 mm) clearance between the pressure plate and the top friction disc with new clutch discs. If the clutch pack clearance exceeds .140 in. (3.6 mm), this indicates some wear of the discs. The friction discs are completely worn out and must be replaced if the clearance exceeds .200 in. (5.1 mm). If the clearance is less than .090 in. (2.3 mm), this indicates that the clutch piston may not be fully retracted or some distortion of the discs may be consuming the clearance. Closely inspect and repair or replace components as required.
NOTE: To ease the measurement of the clutch assembly clearance, gently wedge two standard blade screwdrivers between the pressure plate and disc. Locate the screwdrivers 180° apart. Measure from the top of the pressure plate to the top of the disc while the screwdrivers hold the pressure plate wedged tightly against the retaining ring(s). Call this dimension "A".
NOTE: Remove the screwdrivers and push the pressure plate down against the disc. Again, measure from the top of the pressure plate to the top of the disc. Call this dimension "B".
NOTE: A-B=Clutch pack clearance; the distance the piston travels to compress the discs in the fully applied condition.
It may be advantageous to pre-align the clutch discs and hold them in position for assembly. To do this, remove the two flush plugs (1) from the back side of the clutch housing. Next, install the clutch onto the end of the clutch shaft splines. Install the brake hub onto the clutch shaft and into the clutch assembly, aligning all disc splines. Then, install two 3/8 in. NF x 1 capscrews through the flush plug holes to push the clutch piston against clutch discs and hold them in position. Only tighten the capscrews enough to keep the clutch disc from moving in the housing. Remove the brake hub and clutch shaft. The clutch assembly is now ready for installation.
