1SD-03-1067Bendix® BP-R1™ Bobtail Proportioning Relay ValveDESCRIPTIONThe BP-R1™ bobtail proportioning relay valve is a combina-tion of two individual

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12BW1624 © 2009 Bendix Commercial Vehicle Systems LLC. All rights reserved. 6/2009 Printed in U.S.A.

2FIGURE 3 - BP-R1™ BOBTAIL PROPORTIONING RELAY VALVEINLET-EXHAUSTVALVESPRING(NOT USEDIN ALLMODELS)INLET-EXHAUSTVALVEPROPORTIONINGPISTONCONTROLPORTRELA

3SERVICE BRAKES HOLDING — TRACTOR/TRAILER COMBINATIONThe air pressure being delivered to the brake actuators is also present beneath the relay piston.

4RELAYPISTONINLET-EXHAUSTVALVEINLET-EXHAUSTPISTONPROPPISTONFIGURE 8 - BP-R1™ CONTROL VS. DELIVERY PRESSURERELAYPISTONINLET-EXHAUSTVALVEINLET-EXHAUSTPI

5PREVENTIVE MAINTENANCE GENERAL Important: Review the Bendix Warranty Policy before performing any intrusive maintenance procedures. A war-ranty may b

6FIGURE 10 - BP-R1™ BOBTAIL BRAKE PROPORTIONING RELAY VALVE1030311314111214. Connect the tractor service and emergency “glad hands” (hose couplings)

76. Check the BP-R1™ valve differential pressure by apply-ing 10 psi to the service port and noting the pressure registered at the delivery port. Sub

89. Remove and discard the o-ring (12) from the relay piston (13).10. Remove and discard dust shield (16), if fi tted, and the retaining ring (15) fro

93. Install the small end of the inlet/exhaust valve spring (34) over the rubber of the valve (33), making sure the spring coils rest on the valve’s