Removing and install the trailer braking unit

Immobilise the tractor. Chock the left rear wheel.

If the tractor is not equipped with a Park Lock device, engage the hand brake.

Chock between the frame and the front axle (optional).

Remove the rear right-hand wheel. Place a safety stand under the trumpet housing.

Removal

Remove the complete hydraulic unit comprising the priority blocks (7) and (10). However, if removal does not concern work on the braking unit, the hose for the hydraulic control line (mark (K) ) coming from the brake master cylinders (40 kph tractors) or from the block/valves (tractors fitted with high-pressure braking) should not be disconnected in order to avoid bleeding the hydraulic control line during the final phase.

Install

Legend 

A - Hydraulic unit with two priority blocks for 40 kph tractors - GPA20, GPA30 and GPA40

B - Hydraulic unit with two priority blocks for tractors fitted with a high-pressure braking - GPA20 and GPA40 rear axles

Check :

- that the mating face (F) of the block assembly (7) (10) and of the right-hand hydraulic cover plate are clean;

- the "O" rings (1) to (3) are present.

Lightly smear the thread of screws V with Loctite 242 or equivalent. Tighten these screws to a torque of 25 - 35 Nm.

Connect the hydraulic pipes or hoses. For the pipe or hose (13) of the trailer braking unit (10) proceed as follows:

� GPA20 rear axle 

- Install and tighten the pipe or hose (13) onto the trailer braking unit (10). This return pipe or hose is connected to the GBA20 or GBA25 gearbox.

� GPA40 rear axle (old generation) 

- Position the hose (13) so that it is facing upwards. Tighten the hose. This return hose is connected to the GBA10 gearbox.

- Fill the hose via the quick connector (1), filling it with approximately 0.5 litres of clean transmission oil so as to form a column of approximately 100 mm of oil at the trailer braking unit end (10). This column of oil optimises the operation of the trailer braking system.

� GPA40 rear axle (new generation) 

- Install and tighten the hose (13) for the trailer braking unit (10). This return hose is connected to the GBA15 gearbox.

� GPA30 rear axle 

- Install and tighten the hose (13) for the trailer braking unit (10). This return hose is connected to the GBA10 gearbox.

- Install the hose (50). This hose maintains a column of oil at the inlet of the trailer braking unit (10). This column of oil optimises the operation of the trailer braking system. The hose (50) is connected to the quick fill connector located above the brake master cylinders on 40 kph tractors.

- Position the T connector (1) vertically. Tighten this union and the hoses (13) and (50).

Final steps

Lift the right-hand side of the tractor. Reinstall the wheel. Remove the axle stand. Screw in the wheel screws or nuts depending on version.

If it was necessary to replace or remove the block assembly (7) (10), carry out:

- bleeding of the trailer brake system or the block/valves (tractors fitted with high-pressure braking).

- the hydraulic tests.

Check the tightness of the unions and "O" rings between the two priority blocks and between the inner priority block and the right-hand hydraulic cover plate. Carry out a road test.