SD-03-3412

Bendix® MV-2™ Control Module

2
3 4 7
9

COVER (1)
8
6

RED

1 5
YELLOW

FIGURE 1 FIGURE 2
DESCRIPTION The MV-2™ module includes a spring loaded dual circuit
The Bendix® MV-2™ control module is an integrated control supply valve which selects, as the air source for both control
assembly designed for control panel mounting in a valves, the No. 1 reservoir at all times unless the pressure in
truck-tractor. The bodies for the module, as well as “spool” the No. 1 reservoir falls not more than 30 P.S.I. below that of
inserts, are molded of a nonmetallic, noncorrosive material. the No. 2 reservoir, when the dual circuit supply valve will
The assembly consists of two push-pull valves and a dual shuttle and establish the No. 2 reservoir as the supply. An
circuit supply valve which triggers at a preset pressure auxiliary air delivery port is also available which receives its
differential. The valve “spool” inserts, as well as the dual supply from the dual circuit supply valve. All air connections
circuit supply valve spool and shuttle, may be removed from are at the bottom of the valve, as shown on Figure 3, including
the valve bodies without disconnecting the air lines. the auxiliary air delivery port.

The MV-2™ module provides all the functions of a standard

three valve combination plus supply reservoir source
SB-3
selection:
DELIVERY - TRACTOR
1. Tractor protection control EXHAUST

2. Trailer service air supply AUXILIARY AIR

DELIVERY
3. System park
4. Trailer park only
RESERVOIR #2
TP-3 ™
5. Trailer charge with tractor spring brakes applied (tractor TRACTOR RESERVOIR #2
PROTECTION SUPPLY
park only) VALVE
DELIVERY - TRAILER
RESERVOIR #1
SUPPLY

6. Supply reservoir selection PORT DESIGNATIONS

RESERVOIR #1 MV-2™ CONTROL
MODULE

FIGURE 3

1
The trailer air supply valve (red button) (see Figure 1) delivers Automatic Application
air to the trailer supply line and also will trip (Pop out) With both buttons in, in the normal run configuration, if the
automatically and shut off the trailer supply if pressure supply pressure to the push-pull valves is reduced to
decreases to 40 ±5 P.S.I. 40 ±5 P.S.I., the red button (trailer supply valve) must pop
NOTE: Reservoir No. 1 must be the reservoir that supplies out, applying the emergency or parking brakes on the trailer.
the rear tractor axle(s). If the red button is held in manually and the pressure
decreases to 30 ±5 P.S.I., a tripper piston within the trailer
Reservoir No. 2 must be the reservoir that supplies
control spool will move upward, exhausting the trailer supply,
the front axle.
effecting the required non-override feature. The yellow (parking
The parking brake valve (yellow button) controls the spring brake) button will pop out at approx. 20-30 P.S.I.
brakes on the tractor and when exhausted, simultaneously
causes the trailer supply valve to trip and exhaust, thus PREVENTIVE MAINTENANCE
applying both tractor and trailer parking brakes as required Important: Review the Bendix Warranty Policy before
by Federal Regulations. The trailer brakes may be performing any intrusive maintenance procedures. A warranty
independently released by pushing only the trailer air supply may be voided if intrusive maintenance is performed during
valve (red button) in. the warranty period.
No two vehicles operate under identical conditions, as a
OPERATION result, maintenance intervals may vary. Experience is a
Initial Charge valuable guide in determining the best maintenance interval
for air brake system components. At a minimum, the MV-2™
With the system completely discharged, both buttons are module should be inspected every 6 months or 1500
out (Figure 4). When system pressure reaches 65 P.S.I., operating hours, whichever comes first, for proper operation.
the red button (trailer supply) may be pushed in (Figure 5) Should the MV-2™ module not meet the elements of the
and should stay in, charging the trailer system and releasing operational tests noted in this document, further investigation
the trailer brakes. The yellow button may now be pushed in and service of the valve may be required.
which will supply air to the tractor spring brakes, releasing
them.
Normal Operating Position (Figure 7) SYSTEM PARK

With both buttons pushed in, air is now being supplied to

the trailer and to the tractor spring brakes; all brakes are MV-2 ™
CONTROL
released. MODULE
TP-3 ™
TRACTOR
Actuation of Trailer Park or Emergency Brakes EXHAUST
PROTECTION
VALVE
(Figure 6) SUPPLY TO TRAILER

To actuate the trailer brakes only, the red button is pulled QRV
TRACTOR SPRING BRAKE CONTROL
out, exhausting the trailer supply line. The trailer brakes are
now applied either by air emergency or spring brakes,
SERVICE
depending on the type of trailer system. This mode would RESERVOIR #1

be used to uncouple from the trailer and during bobtail SERVICE

RESERVOIR #2
operation. SB-3

FIGURE 4
System Park (Figure 4)
With both buttons in for normal run modes, the parking
brakes on both tractor and trailer may be actuated by pulling
the yellow (parking brake) button out, which exhausts the CHARGE TRAILER WITH
air from the tractor spring brakes and simultaneously causes TRACTOR PARKED
the red (trailer supply) button to pop out, applying the trailer
brakes. This complies with Federal Regulations that one MV-2 ™
CONTROL
MODULE
control must apply all the parking brakes on the vehicle. TP-3™
TRACTOR
PROTECTION
EXHAUST VALVE
Trailer Charge (Figure 5) SUPPLY TO TRAILER

If both valves are out, parking the combination vehicle, and it

QRV
is desired to recharge the trailer (leaving the tractor spring TRACTOR SPRING BRAKE CONTROL

brakes applied,) the red button may be pushed in

repressurizing the trailer supply line. This mode might also SERVICE
RESERVOIR #1
be used to park a combination vehicle with air actuated
SERVICE
emergency brakes on the trailer to provide demonstrated RESERVOIR #2
SB-3
parking capability with tractor spring brakes only.
FIGURE 5

2
 6. Develop a leak in the tractor spring brake delivery circuit.
The yellow button must pop at 25 ±5 P.S.I. and maintain
supply pressure. Leakage at the exhaust port should
PARK TRAILER WITH not exceed a 1" bubble in 5 seconds.
TRACTOR RELEASED
OR BOBTAIL TRACTOR 7. Charge the system to 120 P.S.I. and push both buttons
MV-2 ™
in. Pull the red button out. The yellow button must remain
CONTROL
MODULE in.
TP-3 ™
TRACTOR
PROTECTION
8. Push the red button in and pull the yellow button out.
EXHAUST
SUPPLY TO TRAILER
VALVE
The red button must pop out almost instantaneously.
9. Install a gauge to monitor tractor spring brake delivery
QRV
TRACTOR SPRING BRAKE CONTROL
pressure. Apply 120 P.S.I. to both reservoirs (No. 1 &
No. 2). Push in the yellow button. Delivery pressure
SERVICE
RESERVOIR #1 should equal the pressure in reservoir No. 1. Reduce
SERVICE the pressure in No. 1 reservoir. Delivery pressure and
RESERVOIR #2
SB-3 No. 1 reservoir pressure should descend together to
105-90 P.S.I. at which point the dual circuit supply valve
shuttle should switch to No. 2 reservoir and delivery
FIGURE 6 pressure should increase to No. 2 reservoir pressure.
After the No. 1 reservoir pressure is reduced to zero,
NORMAL OPERATING
there should not be audible leakage at the No. 1 reservoir
POSITION opening. Close the leak which had been created in the
No. 1 reservoir.
MV-2 ™
10. Leaving the yellow button in, recharge the No. 2 reservoir
CONTROL
MODULE
TP-3 ™
to 120 P.S.I. The delivery pressure should also read
TRACTOR
EXHAUST
PROTECTION 120 P.S.I. Recharge the No. 1 reservoir to 100 P.S.I.
VALVE
SUPPLY TO TRAILER
Slowly vent the No. 2 reservoir. As the No. 2 reservoir
QRV
pressure and the delivery line pressure descend,
TRACTOR SPRING BRAKE CONTROL
pressure should stabilize at approx. 100 P.S.I.
SERVICE 11. Close all vents or leakage points and charge both
RESERVOIR #1
reservoirs to 120 P.S.I. Position the red button out and
SERVICE
RESERVOIR #2
SB-3 the yellow button in. Develop a leak in the spring brake
delivery line and hold the yellow button in. No. 1 reservoir
FIGURE 7 pressure must reduce to zero and No. 2 reservoir
pressure to 20 - 30 P.S.I. The dual circuit supply valve
OPERATING & LEAKAGE TEST shuttle should cycle several times during this leakdown
1. Charge the air brake system to 65 P.S.I. and check for period.
leakage between body seals, body and cover plates.
No leakage permitted. REMOVING AND REPLACING SPOOL ASSEMBLIES

2. With supply pressure still at 65 P.S.I., push the red button Block the wheels or otherwise secure the vehicle and drain
in. The button must stay in. Leakage at the exhaust all reservoirs. It should be unnecessary to remove the MV-2™
port must not exceed a 1" bubble in 5 seconds. module from the vehicle. Remove any panel, plate or whatever
is necessary to expose the valve cover plates. It is
3. Develop a leak in the line delivering air to the trailer supply
recommended that the valve be serviced by replacing the
circuit. The red button must pop at 40 ± 5 P.S.I. and
complete spool assemblies. The dual circuit supply valve
maintain the supply pressure. Leakage at the exhaust
feature may be serviced by replacing four (4) o-rings and
port must not exceed a 1" bubble in 5 seconds.
one (1) spring, available in a maintenance kit.
4. Hold the red button in and again develop a leak in the
supply circuit. Air must start to escape from the exhaust DISASSEMBLY - Spools (Figure 2)
port when the trailer supply line pressure reaches 1. Remove the cover plate screws. (Four in each cover)
30 ±5 P.S.I. and cover (1).
5. Release the red button and rebuild the supply pressure 2. Carefully pull the spool assemblies out of their respective
to at least 40 P.S.I. Push in the yellow button; the yellow body bores by pulling on the buttons.
button must remain in. Leakage at the exhaust port should 3. Remove the roll pins (2) which retain the buttons on the
not exceed a 1" bubble in 5 seconds. spool stems and remove buttons and cover plates.

3
DISASSEMBLY - Dual Circuit Supply Valve SERVICE TEST
1. The dual circuit supply valve is located in the tractor Repeat the “Operating and Leakage Test”.
control body. (The one from which the spool with the
yellow button has been removed.) Grasp the web in the WARNING! PLEASE READ AND FOLLOW
top of the valve spool (3) (Figure 2) with narrow nose THESE INSTRUCTIONS TO AVOID
pliers, twist and pull valve spool out. The shuttle (4) should
also come out with the spool. Remove the shuttle return
PERSONAL INJURY OR DEATH:
spring (5) and o-rings (6), (7), (8) and (9). When working on or around a vehicle, the following
general precautions should be observed at all times.
CLEANING & INSPECTION
1. Park the vehicle on a level surface, apply the
The non metallic components which comprise most of the parking brakes, and always block the wheels.
parts of the MV-2™ module should not be immersed in Always wear safety glasses.
any solvent type cleaner. Old lubricant should be wiped 2. Stop the engine and remove ignition key when
off parts to be reused and the bores of the body wiped out
working under or around the vehicle. When
with a clean dry cloth.
working in the engine compartment, the engine
ASSEMBLY - Dual Circuit Supply Valve (Figure 2) should be shut off and the ignition key should be
removed. Where circumstances require that the
Lubricate o-rings, bore and sliding surfaces with silicone engine be in operation, EXTREME CAUTION should
lubricant Bendix 291126 BW-650-M Dow Corning 55-M. be used to prevent personal injury resulting from
1. Place the shuttle return spring (5) in the dual circuit contact with moving, rotating, leaking, heated or
supply valve bore in the body. electrically charged components.
2. Install o-rings (6) & (7) on the shuttle (4) and (8) & (9) on 3. Do not attempt to install, remove, disassemble or
the valve spool (3). assemble a component until you have read and
3. Insert the small end of the shuttle in the spool and insert thoroughly understand the recommended
the assembly into the valve bore, flush with top of body. procedures. Use only the proper tools and observe
The dual circuit supply valve spool is retained in the body all precautions pertaining to use of those tools.
by the same cover plate which also retains the tractor 4. If the work is being performed on the vehicle’s air
control (yellow button) spool. brake system, or any auxiliary pressurized air
systems, make certain to drain the air pressure from
ASSEMBLY - SPOOLS
all reservoirs before beginning ANY work on the
If old spools are being used, the o-rings and all sliding vehicle. If the vehicle is equipped with an AD-IS™
surfaces should be lubricated with Bendix BW-650-M Silicone air dryer system or a dryer reservoir module, be
Lubricant (291126). If new service replacement spools are sure to drain the purge reservoir.
being installed, they will be pre-lubricated. 5. Following the vehicle manufacturer’s
1. Place cover plates over each plunger stem. The cover recommended procedures, deactivate the electrical
plates are identical and are installed convex side up. system in a manner that safely removes all
2. Place the red button on the longer spool (for trailer air electrical power from the vehicle.
supply), matching the groove in the button with the tongue 6. Never exceed manufacturer’s recommended
in the cover plate (where applicable), and secure the pressures.
button with the button roll pin. Place the yellow button 7. Never connect or disconnect a hose or line
on the shorter spool (for tractor air supply), matching containing pressure; it may whip. Never remove a
button and cover (where applicable) and securing with component or plug unless you are certain all
button roll pin as before. If new service spools are used, system pressure has been depleted.
a new roll pin will be found in each spool package. 8. Use only genuine Bendix ® replacement parts,
3. Insert the shorter spool assembly (yellow button) in the components and kits. Replacement hardware,
tractor supply bore (housing with the dual supply valve). tubing, hose, fittings, etc. must be of equivalent
If the entire valve assembly has been removed, position size, type and strength as original equipment and
the assembly so that the tractor control body housing is be designed specifically for such applications and
at 3 o’clock. With the open bore (trailer supply) at 9 systems.
o’clock, rotate the button until wording on top-center is 9. Components with stripped threads or damaged
horizontally readable. The stepped side of the cover plate parts should be replaced rather than repaired. Do
should be covering the dual supply valve. Secure the not attempt repairs requiring machining or welding
plate with the four flat head Phillips screws; torque to 25 unless specifically stated and approved by the
inch pounds. Insert the longer spool assembly (red vehicle and component manufacturer.
button) in the remaining bore. The stepped sides of the 10. Prior to returning the vehicle to service, make
cover plates should key with each other when the certain all components and systems are restored to
remaining four flat head screws are torqued to 25 inch their proper operating condition.
pounds.
BW1584 © 2004 Bendix Commercial Vehicle Systems LLC. All rights reserved. 3/2004 Printed in U.S.A.