Handbrake and control link


The mechanical control assembly of the handbrake is fitted on drive pinion (9) located on the intermediate housing. It consists of a mechanism (16) placed between six discs (14) that are integral with the drive pinion and four intermediary plates (6). The mechanism housed in a unit (15) fixed to the rear bearing carrier is composed of two cast-iron plates held by springs and separated by ball bearings lodged in raceways. It is operated via a rod (23) fitted on relay pin (26) by means of relay cam (22) which is in contact with rod (19), itself thrusting against a second cam (31) integral via splines with pin (11) controlled by link (3).
- Depending on the type of tractor, the lubrication of the handbrake discs is ensured by an oil mist coming from a central channel and radial drilled holes machined into the drive pinion.
- This centre oil channel also serves to lubricate a needle bearing on those tractors fitted with a creeper unit.


When the handbrake lever is pulled upwards, the cable acts upon link (3) integral with pin (11) via splines.
Pin (11) pivots and turns cam (31) that pushes rod (19) to thrust against a relay cam (22) that turns freely on pin (26), thus causing the spreading of mechanism (16) by way of threaded link pin (23). When the handbrake lever is in the off position, the link (3) returns to its initial position by means of spring (32).
The adjuster nut of the mechanism is accessible via a plug screwed on to the top of the intermediary housing. The oil tightness of housing (7) is provided by seal (12) and that of pin (11) by o’ring (1).


Parts list
(1) O’ring (2) Bolt (3) Link (4) Holding plate (5) Bolt (6) Intermediate plates (7) Housing (8) Bolt (9) Drive pinion (10) Friction ring (11) Pin (12) Oil seal (13) Bearing carrier (14) Disks (15) Housing (16) Spreader mechanism (17) Bolt (18) Washer (19) Rod (20) Pin (21) Adjuster nut (22) Cam
(23) Link (24) Clevis (25) Pin (26) Pin (27) Friction rings (28) Special bolt (29) Mecanindus pin (30) Set screw (31) Cam (32) Spring (33) O’ring (34) Lever (35) Nuts (36) Grower washer (37) Cable (38) Ratchet (39) Quadrant (40) Clevis (41) Rod (42) Shouldered washer (43) Washer (44) Push-button (45) Spring

Disassembling and reassembling the tractor handbrake 

- To carry out operations on the handbrake mechanism comprising discs (14), intermediate plates (6) and mechanism (16), it is necessary to uncouple the tractor and remove the intermediate housing as well as the drive pinion.

Uncouple the tractor between the gearbox and the intermediate housing.
Separate the intermediate housing from the centre housing.
Remove the creeper unit (if fitted). If necessary, remove the sleeve and ratchet of the Park Lock (depending on equipment) and the bearing assembly / hydraulic pump drive pinion. Remove the drive pinion and handbrake unit.

Remove circlip (5).
Loosen and remove bolts (8) Separate the housings (13) (15).
Place the drive pinion on the workbench, the bevel gear at the bottom.
Remove the discs, intermediate plates and the brake mechanism.


Clean and check the components. Replace any parts found to be defective or buckled. Check that the central channel and radial drilled holes of the drive pinion (depending on versions) are not obstructed. Check also, the oil discharge ports located at the base of the handbrake unit housing.
Place carrier (13) on the bearing cone of the drive pinion, with the cup previously lubricated.
Correctly orient control"C". Reinstall mechanism (16) by placing it between discs (14) and the intermediate plates (6) as shown in the overall view. Correctly position stops "T".
Assemble the handbrake (15) on bearing carrier (13).
Install bolts (8) previously lightly smeared with Loctite 270 or its equivalent and tighten to a torque of 120 - 160 Nm. Install circlip (5).
Reinstall the drive pinion unit and handbrake.
Turn and Install axle (25) to mechanism (16) so as to clear it easily. Install the washer and a new split pin. Adjust the control.
Reinstall the bearing / hydraulic pump drive pinion assembly, the ratchet and the Park Lock sleeve (depending on equipment). Install the creeper unit (if fitted). Reassemble the intermediate housing and centre housing.
Couple the tractor between the gearbox and the intermediate housing.
Check the correct operation of all the controls.
Check all the functions (mechanical and electrical) of the handbrake lever.
Road test. Check the oil tightness of the mating faces and the hydraulic unions.

Disassembling, reassembling and adjusting the controls

Remove the entire unit (7) and rod (19). If necessary, take out each component in the unit.
- To take out pin (26) and cam (22), it is necessary to uncouple the tractor between the gearbox and the intermediate housing.
Reverse the order of the previous operations and respect the following special points.

On unit (7)
- Insert friction bush (10) using a locally manufactured drift.
- Insert oil seal (12) in contact with unit (7) using a suitable fixture. After inserting, lubricate the seal.
- lightly smear with Loctite 241 the Philips head bolt (30) of cam (31).
- lightly smear with Loctite 510 the mating face of unit (7) and the intermediate housing.
- Tighten bolts (2) to a torque of 25 - 35 Nm and bolt (17) to a torque of 14 - 20 Nm.
During assembly, do not forget o’ring (1) that provides oil tightness between pin (11) and the link (3).


On cam (22)
- Insert the friction bush (27) flush with face ‘F’.
- Lightly smear bolt (28) with Loctite 542 (solely on an assembly without an o’ring) and tighten to a torque of 25 – 35 Nm.

On cam (31)
- Moderately tighten set screw (30) smeared with Loctite 241.

On the brake mechanism (16)
- Install pin (25) in such a manner as to provide clearance.
- Lightly smear the thread of link rod (23) with Loctite 270 and tighten it in clevis (24).


Adjustment
- With cam (31) in contact with unit (7) via the port located above the intermediate housing, act on nut (21) in order to obtain a clearance "J" of 1.2 mm to 1.3 mm between the discs, intermediate plates and mechanism.


Position link (3) on pin (11) to obtain a dimension of 225 mm to 250 mm between the centre of the cable and cable holder (4) (position A) by checking that cam (31) is in contact with the housing (7).
Check that the travel of the link (3) falls between 30 mm and 45 mm with a force of 10 - 25 daN exerted at the point where the cable is fixed (position B).


- To adjust the tractor handbrake, take off the wheel concerned and slightly tilt the cab to the left , taking care not to damage any of the components attached to it.
Position an axle stand.
- Remove the plug located above the intermediate housing.
- Using a locally manufactured short spanner, adjust nut (21) in order to obtain the travel.
- After adjustment, check the free movement of the tractor with the handbrake in the off position.
- Tightening torque for wheel nuts or studs.

Disassembling, reassembling the handbrake lever and replacing the cable

Disassembling the handbrake lever 
Disconnect the electrical connector (1) to the switch and the handbrake cable (37).
Unscrew the push-button (44).
Recover washers (42) (43) and spring (45).
Remove the clevis assembly (40) and rod (41). If necessary, separate the rod and clevis. Replace the quadrant (39) and ratchet (38).


Reinstall the lever. Reverse the disassembly operations.
Check the correct operation of the lever. If necessary, adjust the handbrake.

Replacing the handbrake cable


Disconnect the endsof the cable and sheath. Remove the handbrake cable.
If necessary, before refitting the new cable, hold it vertically and inject a few drops of Vaseline oil between the cable and sheath. Wait for several moments for the oil to descend the length of the cable.
Carry out the fitting of the cable on its respective fixing points.


- Take care to place the lock washer (1) between nuts (35) on cable holder (4) located above the intermediate housing. This assembly avoids any kinking of the cable during handbrake operation.
Check the following points to ensure correct operation of the handbrake lever:
- put the handbrake on, its initial travel should be approximately 10 to 13 clicks of the ratchet with a force of around 10 - 25 daN exerted at the point of cable connection.
- the signal lamp on the dashboard should light.
- release the handbrake. The assembly should return to the handbrake off position.
- the assembly should operate freely without any "hard" points or sticking.
- in the handbrake off position, the dashboard light must go out.
- On tractors fitted with a Powershift gearbox, first disengage the speed control of the Park Lock in order to get the dashboard light to go out when the handbrake is in the off position.