User's Manual

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SD-13-4796

FIGURE 1 - AR-2

™

ANTILOCK RELAY VALVE ASSEMBLY

DESCRIPTION

The Bendix

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

modied 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 identied with cast, embossed letters for ease of

identication and installation.

Bendix

AR-2

™

AntiLock Relay Valve

ANTILOCK CONTROLLER

MOUNTING HOLES(4)

DELIVERY

SUPPLY

DELIVERY

MOUNTING

BRACKET

CONTROL

SERVICE

Summary of content (12 pages)

PAGE 1
SD-13-4796 ® Bendix® AR-2™ AntiLock Relay Valve ANTILOCK CONTROLLER MOUNTING HOLES(4) MOUNTING BRACKET SERVICE CONTROL SUPPLY DELIVERY DELIVERY FIGURE 1 - AR-2™ ANTILOCK RELAY VALVE ASSEMBLY DESCRIPTION The Bendix® AR‑2™ antilock relay is a specialized air brake valve developed for use on antilock equipped tractors only.
PAGE 2
BLEND BACK PISTON SPRING CONTROL PORT SERVICE PORT SERVICE PISTON EXHAUST INLET/EXHAUST VALVE RELAY PISTON SPRING (NOT IN ALL MODELS) PROPORTIONING PISTON INLET/EXHAUST VALVE SUPPLY PORT DELIVERY PORT EXHAUST FIGURE 2 - SECTIONAL VIEW BENDIX® AR-2™ ANTILOCK RELAY VALVE The letter identification and air hose connections are shown below for reference. Bendix® AR‑2™ VALVE AIR CONNECTION EMBOSSED IDENT.
PAGE 3
ANTILOCK CONTROLLER TRAILER SUPPLY VALVE SERVICE BRAKE VALVE INLET-OPEN EXHAUST-CLOSED RELAY PISTON INLET-OPEN EXHAUST-CLOSED BENDIX® M-21™ MODULATOR REAR AXLE SERVICE CHAMBER FIGURE 3 - TRACTOR SERVICE BRAKES APPLYING - TRACTOR TRAILER COMBINATION SERVICE BRAKES APPLYING ‑ TRACTOR/TRAILER COMBINATION SERVICE BRAKES RELEASING ‑ TRACTOR/TRAILER COMBINATION Brake application air enters the Bendix® AR‑2™ valve service port and is conducted through the service piston then through the center of both the b
PAGE 4
ANTILOCK CONTROLLER TRAILER SUPPLY VALVE SERVICE BRAKE VALVE INLET-OPEN EXHAUST-CLOSED RELAY PISTON INLET-CLOSED EXHAUST-CLOSED BENDIX® M-21™ MODULATOR REAR AXLE SERVICE CHAMBER FIGURE 4 - TRACTOR SERVICE BRAKES HOLDING - TRACTOR TRAILER COMBINATION Once past the inlet and exhaust valve, service air pressure exerts a force on the larger diameter end of the proportioning piston, which opposes the air pressure and spring force exerted on the other end.
PAGE 5
ANTILOCK CONTROLLER TRAILER SUPPLY VALVE SERVICE BRAKE VALVE INLET-OPEN EXHAUST-OPEN/CLOSED INLET-CLOSED EXHAUST-OPEN BENDIX® M-21™ MODULATOR REAR AXLE SERVICE CHAMBER FIGURE 5 - TRACTOR SERVICE BRAKES RELEASING - TRACTOR TRAILER COMBINATION PREVENTIVE MAINTENANCE GENERAL EVERY 3 MONTHS, 25,000 MILES OR 900 OPERATING HOURS 1. Remove any accumulated contaminates and visually inspect the exterior for excessive corrosion and physical damage.
PAGE 6
ANTILOCK CONTROLLER TRAILER SUPPLY VALVE PROPORTIONING PISTON INLET-CLOSED EXHAUST-CLOSED SERVICE BRAKE VALVE BLEND BACK PISTON RELAY PISTON INLET-CLOSED EXHAUST-CLOSED BENDIX® M-21™ MODULATOR REAR AXLE SERVICE CHAMBER FIGURE 7 - SERVICE APPLICATION HOLDING - BOBTAIL TRACTOR ANTILOCK CONTROLLER TRAILER SUPPLY VALVE SERVICE BRAKE VALVE BENDIX® M-21™ MODULATOR REAR AXLE SERVICE CHAMBER FIGURE 8 - TRACTOR SERVICE BRAKES RELEASING - BOBTAIL TRACTOR 6
PAGE 7
2. Stop the engine and remove ignition key when working under or around the vehicle. When working in the engine compartment, the engine should be shut off and the ignition key should be removed. Where circumstances require that the engine be in operation, EXTREME CAUTION should be used to prevent personal injury resulting from contact with moving, rotating, leaking, heated or electrically charged components. 3.
PAGE 8
DASH CONTROL VALVES TRACTOR PROTECTION BRAKE VALVE BENDIX® M-21™ MODULATORS BENDIX® AR-2™ WITH CONTROLLER FIGURE 9 - TYPICAL BENDIX® CR-16™ AIR BRAKE SYSTEM 8. Make a full brake application and note that both test gauges register the same pressure. IMPORTANT: If during testing the service port pressure is SLOWLY increased from approximately 70 psi to a full (100 psi or greater) brake application, the Bendix® AR‑2™ valve MAY begin to cycle between an apply and exhaust mode.
PAGE 9
1 20 22 2 24 26 5 28 6 3 7 21 30 32 34 23 25 36 29 35 8 33 27 31 4 37 38 39 19 18 17 40 9 16 15 14 13 11 12 10 FIGURE 10 - BENDIX® AR-2™ ANTILOCK RELAY VALVE 9
PAGE 10
DISASSEMBLY GENERAL The following disassembly and assembly procedure is presented for reference purposes only and presuppos es that the appropriate maintenance kit is on hand at the time of disassembly. The instructions provided with the maintenance kit should always be used in lieu of those presented here. Refer to figure 10 throughout the disassembly and assembly procedure.
PAGE 11
5. Carefully insert the assembled valve (33) and seat (34) into the proportioning piston (30), making certain that the coils of the valve spring (32) rest on the four tabs of the valve (33). While holding the seat (34) in place, install the retaining ring (36) to secure it in the piston (30). Make certain the retaining ring is fully seated in its groove. O-RING IDENTIFICATION CHART O.D. W 6. Install both the large and small diameter o‑rings (31 & 29) on the proportioning piston (30). 7.