The double crossover braking system allows both sides of the vehicle to brake even if one circuit fails. Each circuit acts on one front wheel and the diagonally opposed rear wheel.All versions are fitted with a 9" brake servo.The vacuum pipe-brake servo connection on petrol vesions is located in a siphon area of the intake manifold to prevent petrol vapours passing through.Versions without ABS are fitted with two constant pressure regulators (In Line Valves) on the brake pump body. Both pressure regulators must be present if the brake system is crossover. The pressure regulators prevent the rear wheels from locking when the vehicle load shifts to the front axle during braking.The remaining versions, without ABS are fitted with a variable load proportioning valve fastened to the body at the rear.The front brakes are disc type. Ventilated brake discs on the 1.3 16v JTD version. The callipers are floating on petrol versions and twin cylinder with automatic play take-up on jtd versions.Rear drum brakes on all versions.
OPERATION
In rest position, the pressure regulator control spring presses the piston fully down in the cylinder, i.e. against the wall of the outlet chamber. Up to an operating pressure of 21.51 bars, Output pressure (OP) corresponds to input pressure (Pi). An increase in input pressure acts on the piston to bring about displacement by overcoming the pressure of the control spring. Under these conditions, the volume increases in the outlet chamber and the pressure in the rear circuit consequently falls by a ratio of 0.15 for each wheel.
