High-pressure brakes

The high-pressure braking unit is fitted to tractors equipped with a GTA1540 or GTA2520 transmission:
- as standard on 50 kph tractors
- as an option on 40 kph tractors
This system is an additional unit located on the right-hand side of the gearbox. It is controlled by the transmission's Autotronic 5 controller and supplied hydraulically by the CCLS system.

The high-pressure braking system is based on the "regulator breaker" principle. Along with the Autotronic 5 controller, this operating principle ensures that the system remains in the right pressure range at all times. (between 80 and 95 bar).

Operating principle of the system 

Supply: The pump for the hydraulic system directs flow into the unit depending on the XLS signal it receives from the system.

Regulation: The valve that controls the supply is the "normally open" type. It controls the supply pressure thanks to the pressure sensor indicating the instantaneous pressure in the unit.

Safety: The accumulator ensures independent braking in the event of a problem. (It guarantees up to 5 braking operations). The unit also has a safety valve that limits the pressure to 100 bar. A 25-micron filter protects the system at the braking unit inlet. A non-return valve maintains the pressure within the system during braking. When carrying out maintenance on the unit, an internal bleed screw enables the accumulator pressure to be eliminated to prevent accidents.

1- Pressure from the pump
2- XLS signal
3- 25 μ filter
4- 100 bar relief valve
5- Accumulator
6- Return to tank
7- Pressure to braking system
8- Internal bleed screw
9- Pressure sensor
10- Solenoid valve

Composition of the system

• "Hydraforce" hydraulic unit: This unit has a spool valve, a non-return valve, a 25 μ filter and an internal bleed screw. It returns the regulated hydraulic pressure to the braking system.
Pressure sensor (TR44): The pressure sensor is fitted to the braking unit. It measures the instantaneous pressure in the system and sends an analogue signal to Autotronic 5 no. 1. It is supplied with 5 V via the voltage converter.
Solenoid valve (L8): The normally closed solenoid valve is fitted to the braking unit. Depending on the supply voltage to the solenoid valve terminals (0 or 12 V), Autotronic 5 enables the braking system pressure to be adjusted (accumulator inflation).
Accumulator: This reserves a sufficient quantity of hydraulic pressure to enable 5 braking cycles as required.

Autotronic 5 no. 1 : Located on the right-hand side inside the cab with a violet disc to identify it. It enables the pressure within the system to be controlled via the voltage converter, pressure sensor and solenoid valve. In the event of a system fault, an error code is displayed on the DCC2 DOT MATRIX screen.
Voltage converter. The voltage converter is Installed inside the cab, in the floor to the right of the operator's seat, and is connected to the transmission harness. It is connected to Autotronic 5 no. 1 in order to convert a voltage of 9.5 V at the controller output to a voltage of 5 V to supply the pressure sensor.