FIGURE 1 - ATR-2™ ANTILOCK TRACTION RELAY VALVEDESCRIPTIONThe ATR-2™ antilock traction relay valve is a specialized airbrake valve developed for use o

103. After installing the unit, perform the “OPERATION &LEAKAGE TESTS” for the air valve before placing thevehicle in service.DISASSEMBLYPREPARATI

11FIGURE 13 - AntiLock Traction Assembly Exploded View12345678910111213141516171819202122232425262728293031323334353637384041424344*Item included in m

12in place, install retaining ring(30) to secure it in thepiston(28). Make certain the retaining ring is fully seatedin its groove. Make sure the va

2OPERATIONGENERALBecause the ATR-2™ valve is actually a relay valve, thefollowing description of operation refers to its function in thevehicle’s air

3FIGURE 4 - SERVICE BRAKE APPLICATIONFIGURE 5 - SERVICE BRAKES HOLDINGCONTROLLERTRACTION SOLENOIDCHECK VALVERELAY PISTONINLET EXHAUSTMODULATORSERVICE

4SERVICE APPLICATION - BOBTAIL TRACTOR(FIGURE 7)When the trailer supply valve (dash control with red octagonalbutton) is activated to disconnect the t

5TRACTION CONTROL - SERVICE APPLICATIONGENERALWhile under the control of an antilock traction controller,the ATR-2™ valve’s solenoid is able to initia

6also and because they are also controlled by the controller,the solenoid valves in the appropriate modulator are openedand closed to gently pump the

7WARNING! PLEASE READ AND FOLLOWTHESE INSTRUCTIONS TO AVOIDPERSONAL INJURY OR DEATH:When working on or around a vehicle, the followinggeneral precaut

8FIGURE 12 - PARTIAL ANTILOCK TRACTION SYSTEM SCHEMATICTypical Antilock - Traction System (partial)REAR AXLEBRAKEMODULATORMODULATORREAR AXLEBRAKESPEED

92. Install a gauge at the ATR-2™ valve service port and atone of the delivery ports, then install a gauge in each.3. Connect the tractor service and