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®
Bendix® MV-3™ Dash Control Module
SD-03-3415
TRAILER
DELIVERY
MOUNTING
PLATE
MOUNTING
HOLES
FIGURE 1 - MV-3™ DASH CONTROL MODULE
SECONDARY
SUPPLY
AUXILIARY
PORT
(OPTIONAL)
(4)
DESCRIPTION
The Bendix® MV-3™ dash control module is a two-button,
push-pull control valve housed in a single body which includes
a dual circuit supply valve and a check valve. The MV-3
valve can duplicate the functions of any existing two or three
valve push-pull system and has the advantages of reduced
plumbing.
The MV-3™ valve body , plungers and spools are made out of
a non-metallic, non-corrosive material. All air connections
are at the back of the valve with the exception of the optional
auxiliary port as shown in Figure 1.
TRACTOR
DELIVERY
TRAILER
DELIVERY
™
EXHAUST
AUXILIARY
DELIVERY
PORT
DUAL CIRCUIT
SUPPLY
VALVE
EXHAUST
PORT
PRIMARY
SUPPLY
BOTTOM VIEW
TRACTOR SERVICE
RESERVOIR #1
TRACTOR
DELIVERY
SECONDARY
SUPPLY
SUPPLY
#1
The MV-3™ valve provides the following functions:
1 - Tractor Protection.
2 - Trailer Service Air Control.
3 - System Park.
4 - Trailer Park Only .
5 - Trailer Charge with T ractor Spring Brakes Applied (Tractor
Park Only).
6 - Supply Reservoir Selection.
7 - Primary & Secondary Reservoir Connections.
DELIVERY
SUPPLY
#2
TRAILER
SUPPLY
LINE
FIGURE 2 - MV-3™ DASH CONTROL MODULE AIR
CONNECTIONS
TRACTOR
PROTECTION
VALVE
TRACTOR
SERVICE
RESERVOIR #2
DELIVERY
TRACTOR
SPRING
BRAKES
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OPERATION
NORMAL OPERATING POSITION (FIGURE 5)
During initial charge, with the system completely discharged,
both buttons are out (Figure 3). When system pressure
reaches 65 P.S.I., the red button (trailer supply) may be
pushed in (Figure 4) and should stay in, charging the trailer
system and releasing the trailer brakes. The yellow button
may now be pushed in which will supply air to the tractor
spring brakes, releasing them.
RED YEL
TRAILER
SUPPLY
LINE
TRACTOR
PROTECTION
VALVE
TRACTOR SERVICE
TRACTOR
SERVICE
RESERVOIR #2
FIGURE 3 - INITIAL CHARGING OR SYSTEM PARK
RESERVOIR #1
TRACTOR
SPRING
BRAKES
With both buttons pushed in, air is supplied to the trailer
and to the tractor spring brakes; all brakes are released.
RED YEL
TRAILER
SUPPLY
LINE
TRACTOR
PROTECTION
VALVE
TRACTOR
SERVICE
RESERVOIR #2
FIGURE 5 - NORMAL OPERATING POSITION TRACTOR &
TRAILER
TRACTOR SERVICE
RESERVOIR #1
TRACTOR
SPRING
BRAKES
ACTUATION OF TRAILER PARKING OR
EMERGENCY BRAKES (FIGURE 6)
To actuate the trailer brakes only, the red button is pulled
out, exhausting the trailer supply line. The trailer brakes
are now applied either by emergency air or spring brakes,
depending on the type of trailer system.
RED YEL
TRAILER
SUPPLY
LINE
TRACTOR
PROTECTION
VALVE
TRACTOR
SERVICE
RESERVOIR #2
FIGURE 4 - TRAILER CHARGED & TRACTOR PARKED
2
TRACTOR SERVICE
RESERVOIR #1
TRACTOR
SPRING
BRAKES
RED YEL
TRAILER
SUPPLY
LINE
TRACTOR
PROTECTION
VALVE
TRACTOR
SERVICE
RESERVOIR #2
FIGURE 6 - TRAILER PARKED TRACTOR RELEASED
TRACTOR SERVICE
RESERVOIR #1
TRACTOR
SPRING
BRAKES
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SYSTEM PARK (FIGURE 3)
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
air from the tractor spring brakes and simultaneously causes
the red (trailer supply) button to pop out, applying the trailer
brakes. This complies with Federal Regulations that one
control must apply all the parking brakes on the vehicle.
TRAILER CHARGE (FIGURE 4)
If both buttons are out when parking the combination vehicle
and it is desired to recharge the trailer (leaving the tractor
spring brakes applied), the red button may be pushed in,
repressurizing the trailer supply line. This mode might also
be used to park a combination vehicle with air actuated
emergency brakes on the trailer to provide demonstrated
parking capability with tractor spring brakes only .
AUTOMATIC APPLICATION
With both buttons in (the normal run configuration), if the
supply pressure to the push-pull valves is reduced to
approximately 20 to 45 P.S.I., the red button (trailer supply
valve) must pop out, applying the emergency or parking
brakes on the trailer. If the red button is held in manually
and the pressure decreases to approximately 20 P.S.I., a
tripper piston within the MV-3™ valve will move upward,
exhausting the trailer supply, effecting the required nonoverride feature.
OPERATIONAL TEST
1. With supply pressure at 120 P .S.I., push the red button in.
The button must stay in.
2. Slowly reduce pressure in both service reservoirs. The
red button must pop when supply pressure drops to 20
to 45 P.S.I.
Note: The yellow button must not pop out before the
red button.
3. Hold the red button in and continue to reduce pressure
in all service reservoirs. Air must start to escape from
the exhaust port when the trailer supply line pressure
reaches 20 P.S.I. minimum.
4. Release the red button and rebuild the supply pressure to
at least 120 P.S.I. Push in the yellow button; the yellow
button must remain in.
5. Charge the system to 120 P.S.I. and push both buttons
in. Pull the red button out. The yellow button must remain
in.
6. Push the red button in and pull the yellow button out.
The red button must pop out almost instantaneously .
7. Build both service reservoirs to 120 P.S.I. Decrease the
pressure at the secondary reservoir. The primary reservoir
pressure should not drop below 100 P.S.I. Repeat the
test for decreasing primary reservoir pressure. The
secondary reservoir pressure should not drop below 100
P.S.I.
8. If the MV -3™ valve fails to operate as described replace
or repair it using genuine Bendix parts.
9. Close all reservoir drain cocks and deliberately caused
leakage points before placing the vehicle in service.
WARNING! PLEASE READ AND FOLLOW
THESE INSTRUCTIONS TO AVOID
PERSONAL INJURY OR DEATH:
When working on or around a vehicle, the following
general precautions should be observed at all times.
1. Park the vehicle on a level surface, apply the
parking brakes, and always block the wheels.
Always wear safety glasses.
2. Stop the engine and remove 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,
be used to prevent personal injury resulting from
contact with moving, rotating, leaking, heated or
electrically charged components.
3. 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.
4. 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 an AD-IS
air dryer system or a dryer reservoir module, be
sure to drain the purge reservoir.
5. Following the vehicle manufacturer’s
recommended procedures, deactivate the electrical
system in a manner that safely removes all
electrical power from the vehicle.
6. Never exceed manufacturer’s recommended
pressures.
7. 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.
8. Use only genuine Bendix® replacement parts,
components and kits. Replacement hardware,
tubing, hose, fittings, etc. must be of equivalent
size, type and strength as original equipment and
be designed specifically for such applications and
systems.
EXTREME CAUTION should
™
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9. Components with stripped threads or damaged
parts should be replaced rather than repaired. Do
not attempt repairs requiring machining or welding
unless specifically stated and approved by the
vehicle and component manufacturer.
10. Prior to returning the vehicle to service, make
certain all components and systems are restored
to their proper operating condition.
1
2
4
16
3
14
16
18
19
15
5
6
7
21
20
12
11
8
9
10
14
18
19
15
21
20
12
CAUTION: Note the orientation of the buttons in relation to
the valve to be sure they will be replaced properly.
DISASSEMBLY OF THE MV-3™ VA LVE
1. Remove the red (1) and yellow (2) buttons from the stems
of the spools on the MV-3™ valve by turning in a
counterclockwise direction.
2. Remove and save the mounting hardware from the four
corners of the cover plate (3).
3. If removing the valve from the vehicle, remove and identify
the air lines from the back of the valve.
4. Remove the six Phillips head screws (4) from the cover
plate (3) and carefully remove the cover plate (3) from
the valve.
5. Remove the cap (5) and o-ring (6) from the bore of the
tripper valve. Remove the piston (7), spring (8), spring (9)
and check valve (10). These parts will all fall out of the
™
cavity of the MV-3
valve by tilting the body forward.
Remove the o-ring (1 1) from its groove on the piston (7).
6. Remove the two main spools from the body of the MV-3
valve by grasping the stem and pulling firmly . Remove
the two springs (12) from the bottom of each spool cavity .
7. Pull the guide spool (14) over the threaded end of one of
the plungers (15). Remove the o-ring (16) from the guide
spool (14). Remove o-rings (18, 19 & 20) and the exhaust
seal (21) from the plunger.
8. Repeat S tep 7 on the remaining spool assembly .
9. Remove the retaining ring (22) from the cavity of the
MV-3™ valve body that contains the dual circuit supply
valve.
10.Pull the check valve seat assembly (23) from the valve.
Remove the two o-rings (24 and 13) from the check valve
assembly . Remove the check valve (17) from the MV-3
valve body .
CLEANING & INSPECTION
The non-metallic components which comprise most of the
parts of the MV-3™ valve should not be immersed in any
solvent type cleaner. Old lubricant should be wiped out with
a clean dry cloth.
™
™
17
13
24
22
FIGURE 7 - MV-3™ DASH CONTROL MODULE PARTS
EXPLODED VIEW
4
23
VALVE BODY
If any visible damage to the body or the spools can be
detected, the complete unit must be replaced.
ASSEMBLY
DUAL CIRCUIT SUPPLY VALVE
1. Lubricate all o-rings and bores with silicone lubricant.
Bendix Pc. No. 291 126 or Dow Corning 55-M.
2. Place the check valve (17) into its seat in the body with
its flat surface facing upward. If necessary , reach into
the body to make sure the valve is seated evenly in the
bore.
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3. Install o-rings (24 & 13) onto the check valve (23). Then
install the assembly into its cavity in the MV-3™ valve
body .
4. Install the snap ring (22) making sure it is fully seated in
its groove.
SPOOLS
1. Install o-rings (18,19 & 20) and the exhaust seal (21)
onto the stem of plungers (15).
15
PLUNGER
18
O-RING
19
O-RING
MATING
EXHAUST
SEAL
BEVEL
I.D.
BEVEL
20
O-RING
4. Repeat Step s 1, 2, and 3 with the remaining components
for the opposite spool.
SHUTTLE AND CHECK VALVE
1. Install o-ring (11) into its groove on the piston (7) and
o-ring (6) onto the cap (5).
2. Install spring (8) on the piston (7) and spring (9) on the
boss of the check valve (10).
3. Install the spring and check valve into its cavity in the
body of the MV-3™ valve (tapered end of check valve to
enter cavity first). Make sure the spring (9) is centered
in the bore.
4. Install the piston assembly into the cavity making sure
the spring (9) mates with the bore of the piston.
5. Install the cap (5) with o-ring (6).
FINAL ASSEMBLY
1. Install the cover plate (3) onto the valve body and retain
with the six Phillips head screws. Torque to 30 in. Ibs.
2. Attach the red (1) and yellow (2) buttons onto the threaded
stems of the spools, making sure that they are oriented
correctly as noted in Step 1 of Disassembly procedure.
3. Reattach the MV -3™ valve to the dash using the hardware
removed in Step 2 of Disassembly. If air lines were
removed during disassembly , reconnect to ports marked
during disassembly . When reconnecting threaded ports
use a liquid thread sealing compound, attach the air line
until it is hand tight and then turn approximately one
and a half turns further (or using a maximum of 10 ft.lbs. torque - Note: overtorquing will crack the port).
21
EXHAUST SEAL
FIGURE 8 - PLUNGER AND EXHAUST SEAL
CAUTION: The exhaust seal (21) must be installed so
that its beveled surface mates with the beveled surface
of the plunger (Figure 8).
2. Install o-ring (16) onto the guide spool (14). Install the
guide spool assembly over the threaded end of the
plunger (15) and press down firmly until it contacts the
plunger flange.
3. Install spring (12) over the boss in the bottom of the
spool cavity in the body of the MV-3™ valve. Place the
spool assembly into the body , keeping the spool square
to the body press and turn the stem until the spool is
fully seated in its cavity. Note the assembly is keyed
and may only be installed one way .
SERVICE TEST
Repeat the Operational T est procedures. T est drive vehicle
at slow speed in a safe area prior to placing back into service.
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BW1613 © 2004 Bendix Commercial Vehicle Systems LLC. All rights reserved. 3/2004 Printed in U.S.A.
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