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BRAKE SYSTEM
501
BRAKES
3. Brakes Held ON :
When the brake pedal is held on, the diaphragm will
momentarily continue to move forward and thus
compresses the outer edges of the reaction disc. This
movement causes the centre of the disc to extrude,
pressing back the input rod and thus closing the
atmospheric port. Thus the output force is balanced
against that of the input force. Further movement of
the brake pedal either opens the vacuum port or the
atmospheric port depending on whether the brake
pedal is released or depressed.
4. Brakes Released
Immediately after the brake pedal is released, the
vacuum port is opened and the atmospheric pressure
in the rear chamber is extracted into the front chamber
and from there to the inlet manifold via the non-return
valve. The atmospheric port remains closed whilst the
input rod assembly returns to its original position as
shown in figure. The diaphragm is then again
‘suspended’ in vacuum until the brake pedal is
depressed.