Section through brake servo assembly - brakes off

Section through brake servo assembly - brakes off

1 Non return valve 2 Housing 3 Diaphragms 4 Minor diaphragm 5 Tie bolt 6 Valve body 7 Valve 8 Valve spring 9 Input rod spring 10 Input push rod 11 Filter

12 Gaiter 13 Piston 14 Ratio disc 15 Reaction disc 16 Central plate 17 Master cylinder 18 Return spring 19 Guide tube 20 Output push rod 21 Bush 22 Air pressures a Partial vacuum b Ambient

Brakes on When the brake pedal is pressed, the input push rod and the piston initially move forward in the valve body. The valve body and output rod then move with the input rod, against resistance from the return spring, to transmit the brake pedal force to the master cylinder assembly.