Bendix Commercial Vehicle Systems E-3 User Manual

Bendix® E-2™ & E-3™ Brake Valves

SD-03-812

DELIVERY
PORTS (4)

CAP SCREW

4

RETAINER
3

O-RING

PISTON

2

RETURN

SPRING

RETAINING

1

FIGURE 1 - E-3™ BRAKE VALVE (SECTIONAL VIEW)

RING

PRELOAD

SPRING

21

PISTON

WASHER

SPRING SEAT

RUBBER SPRING

RETAINER

VALVE SPRING

INLET/EXHAUST
VALVE

O-RING

EXHAUST CH.

VALVE SEAT

O-RING

DIAPHRAGM
WASHER
SCREW

INSERT ASS’Y

7

12

14

15

17

19

20

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 fi tted 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.

8

6

9

13

16

18

11

10

The E-2

TREADLE

MOUNTING

PLATE

DELIVERY
PORTS (4)

AUXILIARY

PORTS (2)

EXHAUST

E-2™ - E-3™ BRAKE VALVE

™

and E-3™ valves have an insert type inlet/exhaust valve

SUPPLY

PORTS (2)

EXHAUST

AUXILIARY

PORTS (2)

SUPPLY

PORTS (2)

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 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).

The E-2™ and E-3™ brake valves utilize a rubber spring confi ned 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 identifi cation washer, located under the retaining ring
in the valve’s exhaust port, provides a means of identifying the E-2™

™

and E-3

brake 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 fl ow by the inlet valve, out
the delivery ports and to the brake actuators, applying the brakes.

1

Balanced

Leakage Test

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 fl ow 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

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 drops 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.

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

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.

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).

Test valve as outlined under “Service Tests.”
NOTE: When installing a new or rebuilt insert, pre-check 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 (11)
from body.

2