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Massey Ferguson 6465, 6480, 6485, 6490 - Rear PTO clutch

MF 6400 Series Tractors Service and Repair

Massey Ferguson 6465, 6480, 6485, 6490 Rear PTO clutch operation

Rear PTO clutch engagement and disengagement are controlled electrically by a proportional solenoid valve, which is itself controlled by the tractor's electronic system. The clutch, located at the front and in the upper section of the centre housing, controls the operation of the rear PTO. It is connected in rotation to the engine flywheel via a vibration damper fixed to the flywheel and a line comprising two shafts.

It consists of a unit (9) supported by two ball bearings (2) (7) centred in a support (32) fitted to the centre housing. The sleeve (27) supports the ball bearing (22), the drive hub (21) and the piston (10). The clutch housing (9) comprises: at the front, a helical gear (28), fixed using screws, which transmits the movement to the hydraulic pumps. For tractors equipped with GTA1540 transmission, gear P1 (28) has spur cut teeth. It is also fixed using screws; at the rear, a bell housing (15) with a set of discs (17) and intermediate plates (14). A sealing ring (3) minimises leakage between the rear end of the gearbox upper shaft and the clutch unit (9).

Clutch engaged position

The rear PTO clutch is supplied via the 17 bar (GTA1040 tractor transmission) or 21 bar (tractors equipped with GTA1540 transmission) low pressure hydraulic system and via a proportional solenoid valve fitted to the right-hand hydraulic cover plate. A transfer pipe hydraulically links the right-hand hydraulic cover plate and the clutch support (32). Pressurised oil enters the unit (9) through hole P and then flows to the rear of the piston (10) via an internal channel. It pushes the piston, which compresses the discs (17) and the intermediate plates (14). The intermediate plates are attached to the bell housing (15) by lugs. The discs are splined to the hub (21). The movement is then transmitted to the rear PTO driving gears via a shaft (35). When the clutch is engaged, the PTO brake piston located in the rear housing is at rest and releases the lower PTO shaftline.

Clutch disengaged position

If the solenoid valve is no longer supplying the rear PTO clutch, the piston (10) is returned against the unit (9) by the spring (18). The oil in the piston chamber is directed to the return by the solenoid valve. The valve ball (8) leaves its seat, thus assisting the decompression of the chamber.

Parts list: (1) Circlip (2) Ball bearings (3) Sealing ring (4) Ring (5) Seal rings (7) Ball bearing (8) Valve (9) Clutch unit (10) Piston (11) "O" ring (12) Belleville progressivity washers (13) Spring support (14) Intermediate plates (15) Bell housing (16) Screw (17) Discs (18) Spring (19) Spring seat (20) Snap ring (21) Drive hub (22) Ball bearing (23) Chamfered washer (24) Countersunk screw (25) "O" ring (26) "O" ring (27) Sleeve (28) Gear (29) Restrictors (31) Circlip used for oil deflector (32) Clutch support (35) Shaft, A - Details, L - Lubrication groove, P - Low pressure groove (17 or 21 bar), P1 - Gear with spur cut teeth (GTA1540 tractor transmission)

Massey Ferguson 6465, 6480, 6485, 6490 - Disassembling the PTO clutch

Remove the clutch. Separate the clutch from its support. Remove the seal rings (5). If necessary, discard them. Remove the screws (16). Remove: bell housing (15); discs (17) and intermediate plates (14); drive gear (28). Secure the front part of the clutch unit (9) in a vice fitted with protective jaws. Remove the screw (24), using a makeshift tool to hold back the spring (18). Remove the chamfered washer (23).

Gradually release the spring (18) using the tool. Remove: hub (21); seat (19); spring (18); support (13); Belleville progressivity washer (12). Remove the piston (10) by firmly striking the clutch unit against the wooden edge of a workbench or failing that, against block of a similar nature. Remove and discard the "O" rings (11), (25) and (26). If necessary, remove the circlip (31) (oil deflector). Extract or drive out: bearing (2) on the support (32); bearing (7) on the unit (9), visually noting the positioning of its sealed face; bearing (22) by first removing the snap ring (20).

Massey Ferguson 6465, 6480, 6485, 6490 - Reassembling the PTO clutch

Clean and check all components. Replace those that are defective. Check the clearance of the valve ball (8) by vertically and rapidly shaking the unit (9): rattling against the unit should be heard. If removed, press fit the sleeve (27) in the unit (9). Before fitting, the fitted section of the sleeve (27) must be lightly smeared with Loctite 648 or equivalent. Clean off any excess Loctite. Check that the various hydraulic ports are not obstructed after the fitting process. Using a press and a suitable fixture in contact with the external surface of the bearing (22), Install the bearing up to the shoulder of the hub (21). Install the snap ring (20).

Position the sealed face of the bearing (7) towards the unit (9). Using a press and a suitable fixture in contact with the internal surface of the bearing (7), Install this bearing against the unit (9). Using a press and a suitable fixture in contact with the external surface of the bearing (2), Install the bearing up to the shoulder of the support (32). After fitting, check that the bearings turn correctly. Install the circlip (31) (oil deflector). Lubricate and Install the new seals (11) (25) (26) on the sleeve (27) and piston (10) respectively. Install the piston using a soft hammer, checking during the fitting process that there are no fragments of seal on its rim.

Reinstall: Belleville progressivity washer (12); support (13); spring (18); spring seat (19). Reinstall the pre-assembled hub (21), using the tool used during disassembly to progressively compress the spring (18). Secure the front part of the clutch unit (9) in a vice fitted with protective jaws. Position the chamfer of the washer (23). Position this washer in the drive hub (21). Lightly smear the thread of the screw (24) with Loctite 270 or equivalent. Tighten this screw to a torque of 24-28 Nm. If the clutch discs (17) have been replaced, the new discs must be soaked for approximately one hour in clean transmission oil.

Stack the new or reused discs and intermediate plates (14), starting with an intermediate plate against the spring support (13). Install the discs and intermediate plates alternately until the number removed during disassembly is reached. Reinstall the bell housing (15) and the drive gear (28) in the correct position. Lightly smear the thread of the screws (16) with Loctite 242 or equivalent. Tighten these screws to 25.5-34.5 Nm. Install the seal rings (5). Reconnect the clutch and its support. Install the assembly.

Massey Ferguson 6465, 6480, 6485, 6490 - PTO clutch removing and install

To remove the rear PTO clutch, the tractor must be separated between the gearbox and the rear axle.

Disconnect the tractor between the gearbox and the rear axle. Remove the right-hand hydraulic cover plate. Remove the 17-bar hydraulic pipe (MF 6465, 6480 tractor) or 21-bar hydraulic pipe (MF 6485, 6490 tractor). This pipe is located at the top right of the mating face of the right-hand hydraulic cover plate on the centre housing. It links the clutch and the right-hand hydraulic cover plate.

Remove: union and the transfer pipe, which are fitted above the centre housing and are used to lubricate the clutch; sensor (1) (MF 6465, 6480); sensors (1) and (2) (MF 6485, 6490). The sensor (1) (output speed) and sensor (2) (input speed) are located above the centre housing. They inform the tractor's electronic system of the clutch behaviour.

Removal

Unscrew the four M12 V screws. These screws fix the support (32) of the rear PTO clutch to the centre housing. Using a suitable tool and the original PTO shaft, remove the clutch complete with support (32) from the centre housing. The support (32) is positioned on the centre housing via two pins P. Remove: sealing ring (3); circlip (1). Separate the support (32) from the rear PTO clutch.

Reinstall

Check the bore of the ring (4) for correct surface condition. If the diagnosis is inconclusive, replace the defective part(s). Check that the seal rings (5) do not show any of the following: hardness; chipping; cuts. Damage to the rings, even if it is minor, risks causing a leak followed by a drop in pressure, which could disrupt the operation of the clutch. If removed, using a press and a suitable fixture, Install and position the ring (4) at a distance of 0.50 mm. This distance is measured between mating face F of the bearing on the support (32) and the end of the ring (4). Check that the hydraulic ports are not obstructed.

Test Install the seal rings (5), new or reused, into the grooves of the shaft of the clutch unit (9). Check that the seal rings turn freely in their grooves. After this check: remove the seal rings and lightly smear with miscible grease; definitively reinstall the seal rings; check that the ends of the seal rings do not protrude beyond the rim of the shaft of the clutch unit (9). Slide the support (32) onto the rear PTO clutch. Install the circlip (1) on the shaft of the clutch unit (9). Check that the circlip is correctly at the base of the groove.

Check that the PTO clutch is not obstructed against its support (32) by ensuring there is a slight clearance between the support and the clutch. Reinstall the sealing ring (3) located at the end of the shaft of the clutch unit (9). Check that the pins (P) are present. Install the clutch and its support (32). Install and tighten screws V to 100-130 Nm. Reinstall: transfer pipe and union used to lubricate the clutch; the 17-bar hydraulic pipe (MF 6465, 6480) or 21-bar hydraulic pipe (MF 6485, 6490) located between the clutch and the right-hand hydraulic cover plate.

Install the sensor(s) by proceeding as follows:

1) MF 6465, 6480 tractor with GTA1040 transmission - Lightly smear the sensor thread (1) with Loctite FORM A Gasket 2 or equivalent. Tighten home the sensor, without forcing, until its end is positioned against the drive hub (21). Unscrew the sensor by three quarters of a turn. Moderately tighten the nut.

2) MF 6485, 6490 tractor with GTA1540 transmission - Lightly smear the sensor thread (1) with Loctite FORM A Gasket 2 or equivalent. Tighten home the sensor, without forcing, until its end is positioned against the drive hub (21). Unscrew the sensor by three quarters of a turn. Moderately tighten the nut. Lightly smear the sensor thread (2) with Loctite FORM A Gasket 2 or equivalent. Tighten home the sensor, without forcing, until its end is positioned against the clutch unit (9). Unscrew the sensor by three quarters of a turn. Moderately tighten the nut.

Reinstall the right-hand hydraulic cover plate. Manually check the backlash between the gear (28) and the hydraulic-pump-driven gears (Load Sensing 110 l/min hydraulic equipment). Reconnect the tractor between the gearbox and the rear axle. Start the engine. Check: operation of the clutch and all hydraulic components; the tightness of the systems.

MF TRACTORS TROUBLESHOOTING
1652	1749	2620	2725	2805
3050	3120	3640	3709	4245
4455	5320	5455	5613	6150
6280	6480	6615	7618	7720