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SD-03-826

Bendix

E-12

™

& E-15

™

Dual Brake Valve

FIGURE 1 - E-12

™

AND E-15

™

DUAL BRAKE VALVES

The E-12

™

and E-15

™

valves are designed such that the

treadle does not sit in an upright position until the air sys-

tem is built up to full reservoir pressure. The supply pressure

moves the primary piston upward transmitting a mechanical

force to the spring retainer and plunger of the treadle

assembly, causing the treadle to move upright.

TREADLE

MOUNTING

PLATE

PRIMARY

DELIVERY

DEL-1

( )

SECONDARY

DELIVERY

DEL-2

( )

PRIMARY

SUPPLY

SUP-1

( )

PRIMARY

SUPPLY

SUP-2

( )

SECONDARY

DELIVERY

DEL-2

PRIMARY

DELIVERY

DEL-1

( )

UPPER

BODY

ASSEMBLY

DESCRIPTION

The E-12

™

and E-15

™

dual brake valves are floor mounted,

treadle operated type brake valves with two separate supply

and delivery circuits for service and secondary braking. The

separation of circuits provides the driver with a graduated

control for applying and releasing the vehicle brakes.

The E-12

™

and E-15

™

brake valves are similar in design with

the exception of the rubber spring (9) and spring retainer (7)

located in the upper body. The rubber spring which is used

in the E-12

™

brake valve alters the performance of the valve

such that the primary circuit delivers full reservoir pressure

to the spring brakes with less treadle travel than that of the

E-15

™

brake valve. See Figure 2 for delivery pressure versus

treadle travel diagram. The greater treadle travel of the E-15

™

brake valve yields a more gradual delivery of air to the spring

brakes resulting in a less sensitive “feel” to the driver when a

brake application is made. This characteristic makes the

E-15

™

brake valve more adaptable to transit vehicle applica-

tions where smooth brake applications contribute to

passenger comfort.

EXHAUST

LOWER

BODY

ASSEMBLY

E-12

™

DUAL

BRAKE VALVE

TREADLE TRAVEL

PRIMARY DELIVERY

(PSI)

E-15

™

DUAL

BRAKE VALVE

TREADLE TRAVEL

PRIMARY DELIVERY

(PSI)

↑↑

↑

↑↑

↑

FIGURE 2 - TREADLE TRAVEL VERSUS DELIVERY

PRESSURE

Summary of content (8 pages)

PAGE 1
SD-03-826 ® Bendix® E-12™ & E-15™ Dual Brake Valve TREADLE MOUNTING PLATE UPPER BODY ASSEMBLY PRIMARY SUPPLY ( SUP-1 ) 11 PRIMARY DELIVERY ( DEL-1 ) 21 PRIMARY SUPPLY ( SUP-2 ) 12 SECONDARY DELIVERY ( DEL-2 ) 22 LOWER BODY ASSEMBLY PRIMARY DELIVERY ( DEL-1 ) 21 SECONDARY DELIVERY ( DEL-2 ) 22 EXHAUST FIGURE 1 - E-12™ AND E-15™ DUAL BRAKE VALVES DESCRIPTION E-12™ DUAL BRAKE VALVE ↑ TREADLE TRAVEL E-15™ DUAL BRAKE VALVE PRIMARY DELIVERY (PSI) The E-12™ and E-15™ brake valves are similar in des
PAGE 2
The circuits in the E-12™/E-15™ valves are identified as follows: The no. 1 or primary circuit is that portion of the valve between the primary piston (2) and the secondary piston (18); the no. 2 or secondary circuit portion consists of the area between the secondary piston and the exhaust cavity. 26 30 32 The supply, delivery and exhaust ports of the E-12™/E-15™ brake valves are identified by designations cast into the valve body adjacent to their associated port. (See Figure 1).
PAGE 3
PLUNGER FORCE 7 PLUNGER FORCE 2 2 8 SUP-1 SUP-1 DEL-1 DEL-1 18 DEL-2 SUP-2 DEL-2 SUP-2 EXHAUST EXHAUST FIGURE 5 - APPLYING - NORMAL OPERATION FIGURE 6 - APPLYING - FAILURE IN THE PRIMARY CIRCUIT APPLYING: NORMAL OPERATIONSECONDARY CIRCUIT PORTION BALANCED: PRIMARY CIRCUIT PORTION The relay piston moves down with the primary piston and closes the secondary circuit exhaust.
PAGE 4
PLUNGER FORCE RELEASING: PRIMARY CIRCUIT PORTION When the force on the brake treadle is released, the mechanical force is removed from the graduation spring (8) and the primary piston (2). Air pressure in the delivery circuit moves the primary piston exhaustive valve, allowing air pressure in the primary piston to exhaust through the exhaust port.
PAGE 5
OPERATION & LEAKAGE CHECKS GENERAL A change in vehicle braking characteristics or a low pressure warning may indicate a malfunction in one or the other brake circuit, and although the vehicle air brake system may continue to function, the vehicle should not be operated until the necessary repairs have been made and both braking circuits, including the pneumatic and mechanical devices are operating normally.
PAGE 6
7 (E-15) 7 (E-12) 23 1 21 9 (E-12) 22 20 8 18 3 19 4 10 2 11 12 4 13 5 14 15 15 14 13 LOWER BODY 12 16 11 10 UPPER BODY 17 FIGURE 10 - EXPLODED VIEW 6 25 24
PAGE 7
DISASSEMBLY The following disassembly and assembly procedure is presented for reference purposes and presupposes that a major rebuild of the brake valve is being undertaken. Several replacement parts and maintenance kits are available which do not require full disassembly. The instructions provided with these parts and kits should be followed in lieu of the instructions presented here.
PAGE 8
1. Using the lubricant provided (Bendix Pc. No. 291126), lightly coat all o-rings, o-ring bores and grooves. Lightly lubricate the primary piston (2) bore into which the graduating spring (8) is installed. While manually depressing and holding the plunger and spring on the piston, slide the plunger and spring retainer (23) into place so that it secures both the plunger and spring to the piston. Make certain the retainer flanges are securely around piston lip and plunger groove. 2.