The 4x2, 6x4 and 8x4 Trakkers mount disc brakes on the front axle (or axles) and drum brakes on the rear axles with final drives in the hubs. The forward drive axle of the 4x4, 6x6 and 8x8 versions are fitted with drum brakes. As of now, there is no technical solution that allows epicyclic final drives and brake discs to coexist, granting easy access to the latter for maintenance. Braking effort is corrected to match the load on the rear axle assembly by the ABS sensors on the wheels, which measures any tendency to jam when braking, and modulate the pressure delivered to the brake cylinders. This system, known as Electronic Braking Limitation (EBL) is an enormous step forward compared to mechanical correctors which depend on the suspension deflection, particularly with suspension systems that have little flexibility.
The compressed air of the braking system is controlled at the compressor output by the APU (Air Processing Unit), which comprises a heated air drier, a pressure regulator, a four-way distributor and two external sockets: one provides the compressed air necessary to inflate the tyres, for example, the other is used to supply the vehicle system from an external source.
Standard and optional retarders
All the Cursor engines are fitted with an ITB vacuum brake (Iveco Turbo Brake, described in the chapter dedicated to the Cursor engines) as standard, and its effectiveness is reinforced by the action of the variable geometry turbocompressor of the 440 and 480 Hp Cursor 8 and Cursor 13 engines.
The ZF hydraulic retarder is available on request with the Ecosplit gearboxes, and its control unit is coupled with that of the ITB. In fact the retarders are activated using the lever on the right, under the steering wheel (the first two notches control the engine retarder alone), and releasing the accelerator completely. Depressing the accelerator again de-activates the retarders, and the telltale on the dashboard will go out. There are two advantages to this system: it prevents the engine from counteracting the retarder should the driver forget to de-activate it, in spite of the telltale on the dashboard, and it allows the retarder to be engaged and disengaged simply by pressing the accelerator pedal, without letting go of the wheel. There is also another automatic function: when the speed governor is activated and the vehicle starts to go downhill, the retarders are engaged to maintain the set speed.
