1
®
SD-13-4796
FIGURE 1 - AR-2
™
ANTILOCK RELAY VALVE ASSEMBLY
DESCRIPTION
The AR-2
™
antilock relay is a specialized air brake valve
developed for use on antilock equipped tractors only. It is
essentially a BP-R1
™
“bobtail” brake proportioning relay valve
(Bendix Service Data Sheet SD-03-1067) with a modified
cover that permits direct attachment of a Bendix
®
antilock
controller such as the EC-15
™
. When combined with an
antilock controller the resulting assembly is referred to as a
antilock controller relay assembly. For example when the
AR-2
™
valve is combined with the EC-15
™
electronic
controller, the resulting assembly is referred to as a CR-16
™
controller relay assembly.
While it is intended for use on antilock equipped tractors,
the AR-2
™
valve functions solely as an air brake relay and
contains no electronics of its own.
The AR-2
™
valve replaces the standard relay valve used to
control the rear axle service brakes and performs the standard
relay function during tractor-trailer operation. During tractor
bobtail operation, the AR-2
™
valve reduces brake application
pressure to the lighter rear axle(s) brakes to improve vehicle
controllability and minimize rear axle(s) wheel skid before
antilock is required. The AR-2
™
valve provides added vehicle
braking control and reduces the number of times antilock is
actually needed.
Like the standard relay valve it replaces, the AR-2
™
valve
and its attached antilock controller is normally mounted near
the service brakes it serves. A mounting bracket, furnished
with the valve, permits either frame or cross member
mounting. All air connections on the AR-2
™
valve are identified
with cast, embossed letters for ease of identification and
installation. The letter identification and air line connections
are shown below for reference.
Bendix
®
AR-2
™
AntiLock Relay Valve
ANTILOCK CONTROLLER
MOUNTING HOLES(4)
DELIVERY
SUPPLY
DELIVERY
MOUNTING
BRACKET
CONTROL
SERVICE
