air brake test

With both buttons in (the normal run con​

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figuration), 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​

[SIZE=2][COLOR=#231f20][LEFT]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.[/LEFT]
[/COLOR][/SIZE][FONT=Arial][SIZE=2][COLOR=#231f20][LEFT]Note: [/LEFT][/COLOR][/SIZE][/FONT][SIZE=2][COLOR=#231f20][LEFT][/left][/COLOR][LEFT][/left][/SIZE][LEFT][/left]

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[FONT=Arial][SIZE=2][COLOR=#231f20]The yellow button [/COLOR][/SIZE][/FONT][COLOR=#231f20][FONT=Arial][SIZE=2][COLOR=#231f20]must not [/COLOR][/SIZE][/FONT][/COLOR][FONT=Arial][SIZE=2][COLOR=#231f20][/COLOR][/SIZE][/FONT][FONT=Arial][SIZE=2][COLOR=#231f20]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[/COLOR][/SIZE][/FONT][FONT=Arial][SIZE=1][COLOR=#231f20]® [/COLOR][/SIZE][/FONT][FONT=Arial][SIZE=2][COLOR=#231f20]valve fails to operate as described, replace
or repair it using genuine Bendix parts.
9. Close all reservoir drain ####s and deliberately caused[/COLOR][/SIZE][/FONT]​

[SIZE=2][COLOR=#231f20]
leakage points before placing the vehicle in service.
[/COLOR][/SIZE]

Note: Bendix is not aware of any federal legislation that specifies the pressure at which the YELLOW
parking brake control valve must automatically "trip" to apply the vehicle parking brakes. This includes the
Federal Motor Carrier Safety Regulations (FMCSR) for in-use vehicles, the CVSA out-of-service criteria,
and the Federal Motor Vehicle Safety Standards (FMVSS) for newly manufactured vehicles. Although
the "trip" pressure for the parking brake control valve is not stipulated for in-use or newly manufactured
vehicles, a parking brake control valve "trip" pressure of 20-40 psi is currently (02/2009) specifi ed as
part of the Commercial Driver License in the CDL Manual. The CDL Manual is not consistent with the​

regulations cited above. See Bulletin TCH-003-051.


Hope this helps....Cheers

 

Sounds like tank filling valve goes bad. I'm not sure what kind of air procession system is used, may be four way valve, may be every valve for every tank.

on some trucks I saw aditional valves that let air fill tnak #1 from tank #2 as redundance thing, but not let #2 tank loose to much air (not lower 4 bar as I remeber)

 

My t2000 is having same problem yellow knob does not pop out till t hits 0psi and even after that it doesnt pop all the way out any ideas whats going on?

 

It may be the knob itself. T2000 has been out of production since 2008, so if you have the original MV3 valve in there, it's seen a whole lotta use by this point.

 

I just changed it right now and same thing pops out close to 0psi