Bendix Commercial Vehicle Systems M-40HF User Manual

Bendix® M-40QR™ and M-40HF™ Pressure Modulator Valves

SD-13-4958

Bendix® M-40QR Modulator

Exhaust Port

(Body has “3, EXH”)

DESCRIPTION

™

Delivery Port

(Casting has

“2, DEL”)

Bendix® M-40HF Modulator

™

Supply Port

(Casting has

“1, SUP”)

Supply

Port

(Casting has

“1, SUP”)

Electrical Connector

Previous Model M-32™ Modulators

Alternate Push-to-

Connect Version,

Showing Optional

Packard Connector

Mounting Holes

(.33" Diameter

Through Body)

FIGURE 1 - M-40QR™ AND M-40HF™ PRESSURE MODULATOR VALVES

Exhaust Port

(Body has

“3, EXH”)

Bendix M-32QR™ (left) and M-32 (right) Modulators

FIGURE 2 - M-32™ MODULATORS

™

The Bendix® M-40QR™ (quick release) and M-40HF™ (high

ow) pressure modulator valves (PMVs) are high-capacity,

on/off air valves that incorporate a pair of electrical solenoids for control. See Figure 1. The solenoids provide

the electro-pneumatic interface between the vehicle’s

electronic control system and the air brake system. For

example, the PMV is used to control the braking function

of service actuators during antilock activity.

The modulator consists of a die cast metal and plastic body that houses one normally-open solenoid, one normallyclosed solenoid, and an inlet and exhaust diaphragm

valve. A three-pin weather-resistant electrical connector

is an integral part of the modulator solenoid assembly

and delivers the vehicle controller’s commands to the modulator. Two mounting holes are provided for frame or

crossmember mounting of the valve.

The Bendix M-40QR modulator is the direct replacement for the Bendix M-32QR modulator (See Figure 2). The Bendix M-40QR modulator has a bias valve to provide an internal quick-release function.

The supply, delivery and exhaust ports on the Bendix M-40

modulators have embossed identication codes.

Port ID

1, SUP Supply

2, DEL Delivery

Air Hose

Connection

Function

Air enters from a valve (typically foot, relay or quick release).

Air is delivered to the service actuators.

3, EXH Exhaust Air is vented to the atmosphere.

FIGURE 3 - PORT DESIGNATION AND FUNCTION

APPLICATIONS

Bendix M-40 modulators may be used for various purposes on a vehicle including ABS and stability interventions. In

applications using these PMVs, an external quick release

valve may also be required, depending on the system

design. Where the modulator is used for individual wheel

control applications, it is typically the last control valve

through which air passes on its way to the service brake

actuator. See Figure 4 for a typical system schematic.

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® AD-IS® air dryer system, a Bendix® DRM™ dryer reservoir module, or a Bendix® 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,  ttings, etc. must be of

equivalent size, type and strength as original

equipment and be designed speci 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 speci 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.

Wheel Speed

Sensor

Air Disc

Brake

Service

Brake

Chamber

Pressure

Modulator

Valve

Antilock Traction

Relay Valve

Pressure

Modulator

Valve

Steering Angle Sensor

Brake Valve

Pressure

Modulator

Valve

Primary Brake

Circuit

Secondary

Brake Circuit

SL-4™ Stop Light Switch

™

TCS

-9000 Trailer

Antilock

Controller

Control Valve

Yaw Rate Sensor

TP-5™ Tractor Protection Valve

Air Disc

Pressure Modulator Valve

Antilock Relay Valve

Pressure Modulator Valve

Slack Adjuster

Brakes

Wheel Speed

Sensor

Glad Hands

Trailer (Control)

Trailer (Supply)

Wheel Speed

Sensor

Service & Spring

Brake Chamber

Spring Brake

Chamber

Service Brake

Chamber

For Illustration Purposes Only, Both Air

Foundation

Drum Brakes

Disc Brakes And Foundation Drum Brakes

Are Shown At Either Side Of The Axles.

FIGURE 4 - TYPICAL SYSTEM DIAGRAM (4S-4M SYSTEM SHOWN)

PRESSURE MODULATOR VALVE (PMV) AND TRACTION CONTROL VALVE (TCV) CHUFF TEST

A wiring harness connects the vehicle modulators to the

controller. The ABS controller is able to simultaneously, and independently, control the individual modulators.

See Figure 5. When ignition power is applied, each modulator solenoid is briey energized. If the air system is

fully charged — and the service brake pedal is depressed during ignition — the modulator creates a single, sharp

audible “chuff” of air pressure. Bendix ECUs will perform a PMV Chuff Test on all installed modulators in the order

Bendix® Electronic Control Units (ECUs) perform a Bendix-

shown in Figure 5. The pattern will then repeat itself.

patented PMV and TCV Chuff Test. The Chuff Test is an electrical and pneumatic PMV test that can assist maintenance personnel in verifying proper PMV wiring and installation. This test is performed only when the vehicle is stationary (if the vehicle moves, the Chuff Test will not

be performed).

NOTE: If there are any active Diagnostic Trouble Codes (DTCs), the stop lamp cross-check portion of the Chuff Test

will not be carried out until all DTCs are fully diagnosed and

corresponding repairs are successfully conducted. The ESP/ATC dash indicator lamp ATC/ESP Lamp — a lamp

that indicates when stability functions, including traction control, roll stability program or yaw control are operating — will also be illuminated when there are active ABS,

ATC or ESP DTCs. (See the Glossary on page 8 for more information on these terms.)

FIGURE 5 - TYPICAL VEHICLE ORIENTATION AND CHUFF SEQUENCE

Right Steer

Driver

Left Steer

1. Steer Axle Right PMV

2. Steer Axle Left PMV

3. Drive Axle Right PMV

4. Drive Axle Left PMV

Foundation

Drum Brakes

Primary Brake

Circuit

Right Drive

Left Drive

5. Additional Axle Right PMV

6. Additional Axle Left PMV

7. Drive Axle TCV

Secondary

Brake Circuit

Right

Additional

Left

Additional

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