Bendix Commercial Vehicle Systems MV-2 User Manual

Bendix® MV-2™ Control Module

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COVER (1)

SD-03-3412

8 6

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FIGURE 1 FIGURE 2

DESCRIPTION

The Bendix® MV-2™ control module is an integrated control assembly designed for control panel mounting in a truck-tractor. The bodies for the module, as well as “spool” inserts, are molded of a nonmetallic, noncorrosive material. The assembly consists of two push-pull valves and a dual circuit supply valve which triggers at a preset pressure differential. The valve “spool” inserts, as well as the dual circuit supply valve spool and shuttle, may be removed from the valve bodies without disconnecting the air lines.

The MV-2™ module includes a spring loaded dual circuit supply valve which selects, as the air source for both control valves, the No. 1 reservoir at all times unless the pressure in the No. 1 reservoir falls not more than 30 P .S.I. below that of the No. 2 reservoir, when the dual circuit supply valve will shuttle and establish the No. 2 reservoir as the supply . An auxiliary air delivery port is also available which receives its supply from the dual circuit supply valve. All air connections are at the bottom of the valve, as shown on Figure 3, including the auxiliary air delivery port.

The MV-2™ module provides all the functions of a standard three valve combination plus supply reservoir source selection:

1. Tractor protection control

2. Trailer service air supply

3. System park

4. Trailer park only

5. Trailer charge with tractor spring brakes applied (tractor park only)

TP-3

TRACTOR

PROTECTION

VALVE

6. Supply reservoir selection

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EXHAUST

DELIVERY - TRAILER

SB-3

RESERVOIR #1

DELIVERY - TRACTOR

RESERVOIR #2

RESERVOIR #1

SUPPLY

AUXILIARY AIR

DELIVERY

SUPPLY

RESERVOIR #2

PORT DESIGNATIONS

MV-2™ CONTROL

MODULE

FIGURE 3

The trailer air supply valve (red button) (see Figure 1) delivers air to the trailer supply line and also will trip (Pop out) automatically and shut off the trailer supply if pressure decreases to 40 ±5 P.S.I.

NOTE: Reservoir No. 1 must be the reservoir that supplies

the rear tractor axle(s). Reservoir No. 2 must be the reservoir that supplies

the front axle.

The parking brake valve (yellow button) controls the spring brakes on the tractor and when exhausted, simultaneously causes the trailer supply valve to trip and exhaust, thus applying both tractor and trailer parking brakes as required by Federal Regulations. The trailer brakes may be independently released by pushing only the trailer air supply valve (red button) in.

OPERATION

Initial Charge

With the system completely discharged, both buttons are out (Figure 4). When system pressure reaches 65 P.S.I., the red button (trailer supply) may be pushed in (Figure 5) 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.

Normal Operating Position (Figure 7)

Automatic Application

With both buttons in, in the normal run configuration, if the supply pressure to the push-pull valves is reduced to 40 ±5 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 30 ±5 P.S.I., a tripper piston within the trailer control spool will move upward, exhausting the trailer supply, effecting the required non-override feature. The yellow (parking brake) button will pop out at approx. 20-30 P.S.I.

PREVENTIVE MAINTENANCE

Important: Review the Bendix Warranty Policy before

performing any intrusive maintenance procedures. A warranty may be voided if intrusive maintenance is performed during the warranty period.

No two vehicles operate under identical conditions, as a result, maintenance intervals may vary. Experience is a valuable guide in determining the best maintenance interval for air brake system components. At a minimum, the MV -2 module should be inspected every 6 months or 1500 operating hours, whichever comes first, for proper operation. Should the MV-2™ module not meet the elements of the operational tests noted in this document, further investigation and service of the valve may be required.

SYSTEM PARK

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With both buttons pushed in, air is now being supplied to the trailer and to the tractor spring brakes; all brakes are released.

Actuation of Trailer Park 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 air emergency or spring brakes, depending on the type of trailer system. This mode would be used to uncouple from the trailer and during bobtail operation.

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 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 5)

If both valves are out, 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 .

CONTROL

FIGURE 4

MV-2

CONTROL

MODULE

EXHAUST

FIGURE 5

MV-2

MODULE

EXHAUST

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SERVICE

RESERVOIR #1

SERVICE

RESERVOIR #2

SERVICE

RESERVOIR #1

SERVICE

RESERVOIR #2

SUPPLY TO TRAILER

TRACTOR SPRING BRAKE CONTROL

CHARGE TRAILER WITH

TRACTOR PARKED

TRACTOR

PROTECTION

SUPPLY TO TRAILER

TRACTOR SPRING BRAKE CONTROL

TP-3 TRACTOR PROTECTION

VALVE

TP-3™

VALVE

™

QRV

SB-3

QRV

SB-3

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