Air Brake Manual

More and more heavy duty vehicles on the road today
are using a dual air brake system. The system has
been developed to accommodate a mechanically
secured parking brake that can be applied in the event
of service brake failure. It also accommodates the
need for a modulated braking system should either
one of the two systems fail. It is actually two brake
systems in one, with more reservoir capacity resulting
in a much safer system. At first glance, the dual
system might seem complicated, but if you understand
the basic air brake system described so far, and if
the dual system is separated into basic functions, it
becomes quite simple.
As its name suggests, the dual system is two
systems or circuits in one. There are different ways
of separating the two parts of the system. On a twoaxle
vehicle, one circuit operates the rear axle and
the other circuit operates the front axle. If one
circuit has a failure, the other circuit is isolated and
will continue to operate.
Basic Dual Air Brake System
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