Bendix AR-1 User Manual

®

Bendix® AR-1™ AntiLock Relay Valve

SD-13-4795

QUICK EXHAUST

DELIVERY PORTS

™

AR-1

ANTILOCK

RELAY VALVE

SERVICE PORT

SUPPLY PORT

TYPICAL

MOUNTING

BRACKET

SUPPLY PORT

QUICK

EXHAUST

™

VALVE

AR-1

WITH ANTILOCK

CONTROLLER

ANTILOCK

CONTROLLER

QUICK/

EXHAUST DIA.

SERVICE

PORT

RELAY

PISTON

INLET/

EXHAUST

VALVE

DELIVERY

PORT

EXHAUST PORT

DESCRIPTION

The AR-1™ antilock relay valve (Figure 1) is a specialized
service brake relay valve. It is essentially an R-14™ relay
valve with a special cover that permits direct attachment of
an antilock controller. When combined with an antilock
controller the resulting assembly is referred to as a antilock
relay controller. For example when the AR-1™ antilock relay
valve is combined with the EC-30™ tractor antilock controller
the resulting assembly is referred to as a CR-30™ antilock
relay controller. While intended for use on antilock equipped
vehicles, the AR-1™ antilock relay valve functions solely as
a service brake relay and contains no electronics of its own.

In an air brake system, the AR-1™ valve serves as a relay
station to speed the application and release of the service
brakes. The valve is normally mounted in proximity to the
service actuators it serves. A mounting bracket furnished

EXHAUST PORT

FIGURE 1 - AR-1™ ANTILOCK RELAY VAL VE ASSEMBLY

with the valve permits either frame or cross member mounting.
All air connections on the AR-1™ valve are identified with
cast, embossed letters for ease of installation. The letter
identification and air line connections are shown below for
reference.

AR-1™ VALVE
AIR CONNECTION EMBOSSED IDENT.

Supply (to reservoir) SUP
Delivery (to brake actuator) DEL
Service (to brake valve rear service delivery) SE R

Like the R-14™ relay valve, the AR-1™ valve incorporates a
quick release valve adjacent to the service port which provides
for rapid exhaust of control air pressure from above the

1

EC-15™ ANTILOCK

CONTROLLER

TYPICAL

MOUNTING

BRACKET

™

AR-1

ANTILOCK RELAY

FIGURE 2 - CR-15™ ANTILOCK RELAY CONTROLLER

relay piston. The standard AR-1™ valve is offered with a 4 psi
crack pressure however with the addition of a various springs
beneath the relay piston higher crack pressures are
possible.

The AR-1™ valve’s internal components are interchangeable
with the R-12™ and R-14™ relay valves therefore the same
maintenance kit is used to service all three valves.

OPERATION

BRAKE APPLICA TION

Brake application air enters the AR-1™ valve’s service port and
encounters the exhaust diaphragm which flexes in response
to the incoming air, sealing the exhaust passage in the cover .
Air flows around the exhaust diaphragm and moves through a
passage in the cover to the top of the relay piston. In response
to air pressure, the relay piston moves into contact with the
exhaust portion of the inlet and exhaust valve. With the exhaust
passage sealed, continued movement of the relay piston
unseats the inlet portion of the inlet and exhaust valve, allowing
supply air from the reservoir to flow out the AR-1™ valve’s delivery
ports to the antilock modulators and then to the brake
actuators. (Figure 3)

2

HOLDING-BALANCED

The air pressure being delivered to the antilock modulators
and brake actuators is also present beneath the relay piston.
When the air pressure above and below relay piston is
equal, the piston moves slightly allowing the inlet valve to
return to its seat. The exhaust valve remains closed. With
both the inlet and exhaust valves closed, air pressure in the
antilock modulators and brake actuators is held stable and
neither increases nor decreases. (Figure 4)

EXHAUST - BRAKE RELEASE

When the brake application is released, air pressure in the
service port of the AR-1™ valve returns to the foot brake valve
and is exhausted. Air , from above the relay piston, flows back
through the cover to the exhaust diaphragm. The diaphragm
flexes in response to the returning air, sealing the service port
and opening the exhaust in the cover. With the exhaust
diaphragm blocking the service port, returning air flows out the
open exhaust. As air pressure is reduced above the relay piston,
pressure beneath it lifts the piston away from the exhaust
valve and opens the exhaust passage. Air from the antilock
modulators and brake actuators returns to the AR-1™ valve
and flows out the open exhaust. (Figure 5)

ANTILOCK

CONTROLLER

EXHAUST

QUICK EXHAUST DIA.

SERVICE PORT

RELAY PISTON

SUPPLY PORT

RESERVOIR

EXHAUST

FIGURE 3 - AR-1™ VAL VE BRAKE APPLICA TION

PREVENTIVE MAINTENANCE

Important: Review the warranty policy before performing

any intrusive maintenance procedures. An extended warranty
may be voided if intrusive maintenance is performed during
this period.

Because no two vehicles operate under identical conditions,
maintenance intervals will vary. Experience is a valuable guide
in determining the best maintenance interval for a vehicle.

INLET/EXH.

VALVE

ANTILOCK

MODULATOR

ACTUATOR

DELIVERY PORT

BRAKE

3. T est air line fittings for excessive leakage and tighten or
replace as necessary.

4. Perform the Leakage T est described in this manual.

EVERY YEAR, 100,000 MILES, OR 3,600
OPERA TING HOURS

1. Perform the Operation and Leakage T est s described in
this manual.

GENERAL

Perform the tests and inspections presented at the
prescribed intervals. If the AR-1™ valve fails to function as
described, or leakage is excessive, it should be repaired or
replaced with a new or genuine Bendix remanufactured
unit, available at any authorized parts outlet.

EVERY 3 MONTHS, 25,000 MILES OR 900
OPERA TING HOURS

1. Remove any accumulated contaminates and visually
inspect the exterior for excessive corrosion and physical
damage.

2. Inspect all air lines connected to the AR-1™ valve for
signs of wear or physical damage. Replace as necessary .

OPERATION & LEAKAGE TESTS

OPERA TING TEST

1. Apply and release the brakes several times and check
for prompt application and release at each wheel. If
prompt reaction is noted at some, but not all wheels,
test the AntiLock modulator between the AR-1™ valve
and the brake actuator for proper operation. If a “sluggish”
response is noted at all wheels, inspect for a kinked or
obstructed air line leading to or from the AR-1™ valve.

2. If a complete release of the brakes is noted at some, but
not all wheels, test the antilock modulator between the
AR-1™ valve and the brake actuator for proper operation.
If an incomplete release is noted at all wheels, inspect
for a kinked or obstructed air line leading to or from the
AR-1™ valve.

3