BENDIX BW1445 User Manual
Bendix® R-7™ Modulating Valve
SD-03-4504
EXHAUST
MOUNTING
HOLE (2)
DELIVERY (2)
MOUNTING
HOLE (2)
BALANCE
INVERTED R-7™ VALVE
CONTROL
PORT
SUPPLY PORT
SUPPLY
CONTROL
EXHAUST
BALANCE PORT
MOUNTING
SURFACE
INLET
VALVE
SPRING
INLET
EXHAUST
VALV E
INLET
VALVE
SEAT
BALANCE
PISTON
INNER SPRING
OUTER SPRING
EXHAUST
CONTROL
PORT
CONTROL
PISTON
DOUBLE CHECK
VALVE
(SUPPLY PORT &
BALANCE PORT)
SINGLE
CHECK
VALV E
DELIVERY
PORT (2)
Some early versions
featured an adjusting screw
FIGURE 1 ‑ EXTERIOR & SECTIONAL VIEW. INSET FIGURE 2 - INVERTED VIEW
DESCRIPTION
The Bendix® R‑7™ modulating valve is used in conjunction
with a dual air brake system and spring brake actuators.
Typically the R‑7 modulating valve performs four functions:
1. Limits hold‑off pressure to the spring brake actuators.
2. Provides a quick release of air pressure from the spring
cavity of the spring brake actuator allowing a fast
application of the spring brake actuators. The valve
delivers air to the park brake quick release valve (or
relay) and also releases air in the control line to the
quick release valve (or relay).
3. Modulates spring brake actuator application should a
failure occur in the primary service brake system.
4. Prevents compounding of service and spring forces.
The valve has one 1/4" control, one 3/8" supply, one 1/4"
balance, two 3/8" delivery NPTF ports, and an exhaust
port protected by an exhaust diaphragm. The valve
incorporates two 13/32" holes for mounting.
Note for model year 2001 and later International®
Trucks only: There is an inverted R‑7 valve, which
appears inverted from the other pictures in this document.
A standard R‑7 valve and an inverted R‑7 valve are not
interchangeable. See Figure 2 for a picture of an inverted
R-7 valve.
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GENERAL SAFETY GUIDELINES
WARNING! PLEASE READ AND FOLLOW THESE INSTRUCTIONS
TO AVOID PERSONAL INJURY OR DEATH:
When working on or around a vehicle, the following guidelines should be observed AT ALL TIMES:
▲ Park the vehicle on a level surface, apply the
parking brakes and always block the wheels.
Always wear personal protection equipment.
▲ Stop the engine and remove the ignition key
when working under or around the vehicle.
When working in the engine compartment,
the engine should be shut off and the ignition
key should be removed. Where circumstances
require that the engine be in operation, EXTREME
CAUTION should be used to prevent personal
injury resulting from contact with moving,
rotating, leaking, heated or electrically-charged
components.
▲ Do not attempt to install, remove, disassemble
or assemble a component until you have read,
and thoroughly understand, the recommended
procedures. Use only the proper tools and
observe all precautions pertaining to use of those
tools.
▲ If the work is being performed on the vehicle’s
air brake system, or any auxiliary pressurized air
systems, make certain to drain the air pressure
from all reservoirs before beginning ANY work
on the vehicle. If the vehicle is equipped with a
Bendix
dryer reservoir module, or a Bendix
®
AD-IS® air dryer system, a Bendix® DRM™
®
AD-9si™ air
dryer, be sure to drain the purge reservoir.
▲ Following the vehicle manufacturer’s
recommended procedures, deactivate the
electrical system in a manner that safely removes
all electrical power from the vehicle.
▲ Never exceed manufacturer’s recommended
pressures.
▲ Never connect or disconnect a hose or line
containing pressure; it may whip. Never remove
a component or plug unless you are certain all
system pressure has been depleted.
▲ Use only genuine Bendix
®
brand replacement
parts, components and kits. Replacement
hardware, tubing, hose, fi ttings, etc. must be of
equivalent size, type and strength as original
equipment and be designed specifi cally for such
applications and systems.
▲ Components with stripped threads or damaged
parts should be replaced rather than repaired.
Do not attempt repairs requiring machining or
welding unless specifi cally stated and approved
by the vehicle and component manufacturer.
▲ Prior to returning the vehicle to service, make
certain all components and systems are restored
to their proper operating condition.
▲ For vehicles with Automatic Traction Control
(ATC), the ATC function must be disabled (ATC
indicator lamp should be ON) prior to performing
any vehicle maintenance where one or more
wheels on a drive axle are lifted off the ground
and moving.
▲ The power MUST be temporarily disconnected
from the radar sensor whenever any tests USING
A DYNAMOMETER are conducted on a Bendix
®
Wingman® Advanced™-equipped vehicle.
▲ You should consult the vehicle manufacturer's operating and service manuals, and any related literature,
in conjunction with the Guidelines above.
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