Issue Date 01 January 2012
Information
Method of Inspection
Reason for Rejection
If the pressure or vacuum gauge
has no warning mark, the following
reference values should be used when
assessing whether there is still enough
pressure or vacuum in the system:
·
45psi (3.1kg/sq cm or 3 bar) for a
pressure gauge
·
10” to 12” (25 to 30cm) for a
vacuum gauge.
5.
By applying the service brake
repeatedly, gradually empty the
braking system, and
a.
if a gauge is fitted, note that:
·
the reading on the gauge
falls steadily each time the
brake pedal is depressed,
and
·
when the gauge needle has
reached the “warning mark”,
there is still enough pressure
or vacuum in the system to
allow the brake to be applied
at least twice more with
pressure or vacuum
assistance
b.
if a warning light or other device
is fitted, check that, after the
warning has operated there is
still enough pressure or vacuum
in the system to allow the brake
to be applied at least twice more
with pressure or vacuum
assistance.
6.
Completely empty the reservoir by
repeatedly pressing the service
brake pedal. Start the engine and
if diesel run it at just below the
governed speed or 2000 rpm if
petrol. Note the time it takes for
the warning device to stop
operating.
5.
a.
Insufficient pressure or
vacuum to give assistance to
brakes for at least two or more
applications after the gauge
has reached the warning mark
b.
insufficient pressure or
vacuum to give assistance to
brakes for at least two or more
applications after the warning
light or other device has
operated.
6.
The time between starting the
engine and the warning device
ceasing to operate or the gauge
showing a safe reading indicates
that build-up of pressure/vacuum
is too slow.
For example:
·
more than 3 minutes for
pressure systems
·
1 minute for vacuum systems.
3.3
Service Brake Control
