Bendix-commercial-vehicle-systems BP-1 BRAKE PROPORTIONING VALVES User Manual download pdf

SD-03-952

Bendix

BP-1

™

Brake Proportioning Valves

FIGURE 1 BP-1

™

BRAKE PROPORTIONING VALVES

1.5

.340”

MOUNTING

HOLES (2)

I.D. TAG STAMPED

BP-1 FRONT OR

BP-1 REAR

3/8 P.T.

SUPPLY PORT

3/8 P.T.

DELIVERY PORT

1/8 P.T.

CONTROL PORT

PIECE NO.

STAMPED HERE

DESCRIPTION OF THE BP-1

™

VALVES

The BP-1

™

brake proportioning valves are incorporated into

the air brake systems to improve the controllability and

reduce the stopping distance of bobtail tractors during

braking. BP-1

™

, front and rear, valves reacting to the lack of

pressure in the trailer supply line reduce the braking effort

on the rear axles and increase the braking effort on the front

axle of tractors operating in the bobtail mode. Treadle

application force during bobtail operation resembles treadle

application force during normal operation with a connected

trailer.

A typical brake proportioning system is shown in Figure 6.

The system consists of a front and a rear brake proportioning

valve and a TR-3

™

valve.

Caution: The BP-1

™

front and BP-1

™

rear valves are similar

in appearance but are NOT interchangeable. Note

identification tag attached to one of the cover

screws (Figure 1); it will be stamped ‘BP-1 Front’

or ‘BP-1 Rear’. The BP-1

™

rear valve can be used

without installing a BP-1

™

front valve, providing the

vehicle does not have a front axle ratio valve. If the

vehicle has a front axle ratio valve, the ratio valve

must be replaced with a BP-1

™

front valve.

OPERATION

A tractor that is equipped with the BP-1

™

rear brake

proportioning valve and TR-3

™

valve only will respond in the

following manner. With the trailer supply valve pushed in

and a service brake application made, equal pressure (100%

of service application) will be delivered to each axle of the

tractor and trailer. When the trailer is disconnected from the

tractor and the trailer supply valve is pulled out, the front

axle of the tractor will receive 100% of the service brake

application pressure and the rear axle or axles approximately

25%. As application pressure increases, the differences

between the front axle and the rear axle(s) pressures

diminish.

1 2 3 4 5 6

Summary of Contents

Page 1 - Brake Proportioning Valves

1®SD-03-952Bendix® BP-1™ Brake Proportioning ValvesFIGURE 1 BP-1™ BRAKE PROPORTIONING VALVES1.5.340”MOUNTINGHOLES (2)I.D. TAG STAMPEDBP-1 FRONT ORBP-1

Page 2 - DELIVERY PRESSURE (PSI)

2FIGURE 2 PERFORMANCE CURVE FOR NOMINALBP-1™ BRAKE PROPORTIONING REAR VALVEA tractor that is equipped with both a front and rear axlebrake proportioni

Page 3 - PERSONAL INJURY OR DEATH:

3FIGURE 4 BP-1™ REAR BRAKE PROPORTIONING VALVECUTAWAY VIEWdelivers 50% of the service application to the actuators.Service pressures above 40 psi begi

Page 4 - OPERATIONAL CHECKS

4TRACTORPROTECTIONVALVETEE FITTINGEXISTING REARAXLE SERVICEDELIVERY LINEREARAXLESERVICERELAYVALVEREAR AXLESERVICERESERVOIRTEE FITTING9. Components wit

Page 5 - FROM VEHICLE

52. Build system pressure to governor cut-out setting.3. Make a service brake application with the foot valve andhave another person or persons observ

Page 6

6REMOVAL OF BP-1™ FRONT VALVE FROMVEHICLE1. Secure the vehicle on a level surface by means otherthan the brakes.2. Drain the air system completely mak

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Bendix-commercial-vehicle-systems BP-1 BRAKE PROPORTIONING VALVES User Manual

Browse online or download User Manual for Equipment Bendix-commercial-vehicle-systems BP-1 BRAKE PROPORTIONING VALVES. Bendix Commercial Vehicle Systems BP-1 BRAKE PROPORTIONING VALVES User Manual

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