Bendix E-2-E-3 BRAKE VALVES User Manual

Bendix® E-2™ & E-3™ Brake Valves

CAP SCREW

PISTON

RETAINER

O-RING

WASHER

SPRING SEAT RUBBER SPRING

SD-03-812

PISTON

RETURN

SPRING

RETAINING

FIGURE 1 E-3™ BRAKE V ALVE (SECTIONAL VIEW)

RING

PRELOAD

SPRING

RETAINER

VALVE SPRING

INLET/EXHAUST VALVE

O-RING

EXHAUST CH.

VALVE SEAT

O-RING

DIAPHRAGM WASHER SCREW

INSERT ASS’Y

DESCRIPTION

The Bendix® E-2™ and E-3™ brake valves are single circuit brake valves that provide the driver with single point control of the service braking system. The valve can be either treadle operated or fitted with a lever for a linkage connection to a conventional brake pedal. Movement of the treadle or pedal controls the graduated application and release of air pressure to the vehicle brake actuators, applying or releasing the vehicle brakes.

The E-2™ and E-3™ brake valves utilize a rubber spring confined in a retainer, resulting in reduced plunger travel as compared to previous design single circuit brake valves.

The E-3™ brake valve differs from the E-2™ valve in that it employs a different piston (see insert Fig. 1), which requires greater plunger travel. Because of the greater plunger travel, the E-3™ valve provides less sensitivity in the 0-40 psi application range as compared to the E-2™ valve. Other than the different pistons, the E-2™ and E-3™ valves are identical. An identification washer, located under the ret aining ring in the valve’s exhaust port, provides a means of identifying the E-2™ and E-3™ brake valve.

The E-2™ and E-3™ valves have an insert type inlet/exhaust valve assembly which can be removed without disconnecting air lines. An exhaust check valve in the bottom of the insert prevents contaminants from entering the valve through the

TREADLE

MOUNTING

PLATE

DELIVERY PORTS (4)

AUXILIARY PORTS (2)

EXHAUST

E-2™ - E-3™ BRAKE V AL VE

SUPPLY

PORTS (2)

exhaust port. An optional exhaust extension is available should an exhaust carry-off line be required.

Porting consists of two (2) 1/2 inch p.t. supply ports, four (4) 3/8 inch or 1/2 inch p.t. delivery ports, and two (2) 1/4 inch p.t. accessory ports (in the supply portion of the valve).

OPERATION

Applying

Applying the treadle or pedal exerts a force on the plunger, rubber graduating spring and piston. The downward movement of the piston causes the piston stem (which is the exhaust seat) to contact the valve, closing the exhaust. As the exhaust closes, the inlet valve moves away from its seat. Air pressure is then allowed to flow by the inlet valve, out the delivery ports and to the brake actuators, applying the brakes.

Balanced

When the air pressure in the cavity beneath the piston and the air pressure being delivered to the brake actuators equals the mechanical force on the top of the piston, the piston lifts and the inlet valve closes, cutting off any further flow of air from the supply line through the valve. The exhaust remains closed, preventing any escape of air through the exhaust port.

When applications in the above average pressure range are made, the valve reaches a balanced position as the air pressure beneath the piston equals the effort exerted by the driver’s foot on the pedal or treadle. When the piston is pressed down all the way , the inlet valve remains open and reservoir pressure is delivered to the actuators.

Releasing

Fully apply valve and hold application. Coat exhaust port with soapsuds. NO leakage permitted. Coat area around top of valve with soapsuds. NO leakage permitted.

If the valve does not function as described or leakage is excessive, it is recommended that it be replaced with a new or remanufactured unit, or repaired with genuine Bendix parts available at our distributors.

When the treadle or pedal application is released, mechanical force is removed from the top of the piston, air pressure beneath the piston lifts the piston; (the inlet valve is closed) the exhaust in the valve is open and the air beneath the piston and in the delivery lines is exhausted through the exhaust port.

PREVENTIVE MAINTENANCE

Important: Review the warranty policy before performing

any intrusive maintenance procedures. An extended warranty may be voided if intrusive maintenance is performed during this period.

Because no two vehicles operate under identical conditions, maintenance and maintenance intervals will vary . Experience is a valuable guide in determining the best maintenance interval for any one particular operation.

Visually check for physical damage to the brake valve such as broken air lines and broken or missing parts.

Every 3 Months, 25,000 Miles or 900 Operating Hours Lubricate all mechanical actuation (pedal) parts with light

(10W) oil. Apply 2 to 4 drop s of oil between the plunger and mounting plate. DO NOT OVER OIL!!!

Lever/linkage operated valves should be adjusted so that the roller just contacts plunger . Check for integrity of mounting plate and treadle and/or pedal.

SERVICE TESTS

Operating Test (IMPORTANT!!! Tests should be conducted with an accurate test gauge.)

Install gauge in a delivery port or line; depress the treadle or pedal to several positions between fully released and fully applied positions, checking the delivery pressure on the gauge to see that it varies proportionately with the movement of the treadle or pedal. In the fully applied position, the reading on the gauge should be approximately that of full reservoir pressure. Upon release of the application, the reading of the test gauge should fall to zero psi immediately .

Leakage Test

With 100 psi supply pressure and valve in released position, coat exhaust port with soapsuds arid check for leakage. NO leakage permitted.

REMOVING AND INSTALLING

Removing

Block and hold vehicle by means other than air brakes. Drain air brake system. *If only the insert is to be removed, remove retaining ring,

and pull insert out. If entire valve is to be removed, disconnect air lines from

valve. Remove mounting bolts and remove valve.

Installing

Clean air lines connecting to valve. Install valve and tighten mounting bolts. Connect air lines to valve (plug any unused ports). T est valve as outlined under “Service Tests.”

NOTE: When installing a new or rebuilt insert, precheck

movement of the inlet and exhaust valve in the exhaust seat by depressing the insert. Precaution should be taken to prevent damage to the inlet and exhaust valve and the exhaust check valve grommet, when installing the insert in the valve. After placing the insert in the valve body, depress the exhaust check valve seat and install the retaining ring. Make sure the retaining ring snaps into the body groove.

DISASSEMBLY

NOTE: Disassembly and assembly instructions are keyed

to Fig. 1 sectional view.

1. Remove treadle or lever assembly, boot and plunger .

2. Depress piston assembly and remove retainer (4).

3. Remove piston assembly (7) and piston return spring (2) from body .

4. Remove o-ring (3) from piston (7).

5. Remove cap screw (6), washer (8), spring seat (9), and rubber spring (10) from piston assembly (7).

6. Remove retaining ring (1) and inlet/exhaust insert assembly (1 1) from body.

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