Need info on installing a dump valve

Discussion in 'Flatbed Trucking Forum' started by Southern Flyer, Dec 31, 2012.

  1. Autocar

    Autocar Road Train Member

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    Been eating at the lunch counter again, haven't you?
     
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  3. Autocar

    Autocar Road Train Member

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    The Hot Rod Shop Oxford, AL
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    Really? Someone should tell the engineers at Fontaine, because they put my leveling valve on the rear axle and the dump valve, they put on it, only dumps the rear bags.

    The supply line comes into the leveling valve and one line comes out to a T fitting, to supply the bags. One side of the T goes to the front axle, one side goes to the rear bags. The dump valve goes in the line from the T to the rear bags.
     
    Hanadarko and SHC Thank this.
  4. daf105paccar

    daf105paccar Road Train Member

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    Autocar,have you ever used the the last axle dump for a longer time?


    My point is that because the leveling valve is on the last axle,if that axle raises (or the chassis off the trailer goes down a little)it will lower the airpressure off the airbags off the front axle.
    Which is something that would happen because you dump the air out off the bags off the last axle.
    Unless Fontaine puts a block on the airlines going to the front airbags at the moment you dump the last axle.
     
  5. Autocar

    Autocar Road Train Member

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    The Hot Rod Shop Oxford, AL
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    I've screwed up and forgot to shut it off, on occassion, and yep, it keeps on dumping. However, a dump valve is not for running around all the time with it dumped. It is for dumping for the few seconds necessary to make the turn, then shutting off.
    You stated that it won't work, with the leveling valve on the rear axle. The fact is, it does work at what it was designed for, which does not include leaving the rear axle dumped as you run all around Dixie.
    Semi-Crazy's sketch is correct.
     
  6. daf105paccar

    daf105paccar Road Train Member

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    Correct.

    While having a piece off pie(it is afternoon here) i had a rethink.
    It can work for limited time.

    So i guess we were both wrong and both right at the same time.:biggrin_25514:
    Isn't nice if 2 people can debate something and not have a fight? :biggrin_25525:
     
  7. Semi Crazy

    Semi Crazy Road Train Member

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    Middle Tennessee
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    When the trailer frame lowers the HCV will add more air. Since the rear dump valve is now blocking air to the rear bags the front bags will continue to fill with air until the HCV reaches it's neutral point again.

    Have some more pie!
     
  8. Cat sdp

    Cat sdp . .

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    I don't know about spreads but with a tri- axle lifting the axle around a corner will get you cut back to 80k and a large $$$ ticket. And I don't eat lunch at a counter.

    I know it's apples and oranges............


    PS. I like blueberry ................
     
  9. daf105paccar

    daf105paccar Road Train Member

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    Correct sir.
    Like i said i had a rethink.
    And don't forget,it is New Year's Day,not when a person is at his prime in his thinking.:biggrin_25525:
    I didn't edit my previous posts with my mistake in ,as this would screw up the whole thread.


    But do you mind if i stick too regular pie?:biggrin_2559:


    But here's another question for you,does the HCV limit itself to how much pressure it puts on the front bags?
     
  10. ralph

    ralph Road Train Member

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    I have never seen a HCV with a built in regulator. I have had my suspension guage over 120 psi.
     
    Semi Crazy Thanks this.
  11. Southern Flyer

    Southern Flyer Bobtail Member

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    Sep 21, 2012
    Rockmart, Ga
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    AirBags.jpg Here is a picture of what I've got right now, so I need to eliminate the long air lines on each side that run to the front and back bags and just use one side of the T from the HCV to the front then the other to the rear and then put the dump in the line going to the rear bags? The valve I have is a 2 wire 3 port electric solenoid that also is used for a air fan clutch, will this work or is it not gonna dump the air off fast enough. The parts guy at Great American suggested that it would work for what I need. AutoCar I'm in Oxford a pretty good bit if you wanna come out and school me on this in person.
     
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