Air Dryer bypass

Discussion in 'Questions From New Drivers' started by Scorpion7681, Nov 26, 2007.

  1. Nov 26, 2007 #1
    Scorpion7681

    Scorpion7681 Bobtail Member

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    Nov 26, 2007
    Vancouver, WA
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    Hi, Im hoping someone can help me or lead me into the right direction.
    I have some knowlege of the air dryers on 'trucks' from my job in the Army National Guard (I am a 63B Wheeled vehicle mechanic).

    I have many friends that are truck drivers and yesterday I went on my first trip with one of them. It was a short ride but on this trip, he discovered something new with his truck. As we were driving down the freeway, the air dryer or something that holds air would release air about every 10 seconds. Now I know that the tanks get full and the excess is released... but this was too often. Under a load it was more often. He took it to a mechanic on his way to LA and they bypassed it, they also said it was full... (thats where I got lost). Now he has to drain the tanks when he stops.

    Im looking for the right part so he can tell his company mechanic what to order or replace only once (its a small company and the mechanic isn't too bright sometimes)

    I think its a pressure release valve or something but, I figure I would ask the truckers :biggrin_25525:
     
    Scorpion7681, Nov 26, 2007
    Scorpion7681, Nov 26, 2007
    #1
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  3. Nov 26, 2007 #2
    heyns57

    heyns57 Road Train Member

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    Dec 30, 2006
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    I think he needs a new spit valve on the air dryer. It was spitting continuously, so they bypassed the dryer and it is now necessary to drain the tanks manually.

    There is also a safety valve on the first tank, the wet tank, that opens at about 150 psi. If the air pressure governor does not cycle properly between 90 and 120 psi, air pressure can build up until the safety valve opens. There is no way to bypass the safety valve, and a problem there would not require manual draining of the tanks.
     
    heyns57, Nov 26, 2007
    heyns57, Nov 26, 2007
    #2
  4. Nov 26, 2007 #3
    AllLab

    AllLab Light Load Member

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    Nov 4, 2007
    changes daily
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    What he is going to need is Dessicant Cartrige and a purge valve kit!
    depending on what type and model he has there are many. The best thing to do is get the VIN#/serial# of the truck and call the dealer as they can
    look it up, as long as it came on the truck from the factory, if it did'nt
    you'll have to get a good partsman to look at it to Identify it. When they say it's full the dessicant/Medium that dries the air going through the system gets saturated with moisture, sometimes its oil from an air compressor going bad so make sure its not oil! Be sure to take care of it though because you could have a problem with your air lines freezing up
    in cold weather! Hope this helps!
     
    AllLab, Nov 26, 2007
    AllLab, Nov 26, 2007
    #3
  5. Nov 27, 2007 #4
    Scorpion7681

    Scorpion7681 Bobtail Member

    4
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    Nov 26, 2007
    Vancouver, WA
    0
    thanks for all your help, it was very appreciated. :) Ill let you all know how it turns out when he arrives back here about Wednesday.
     
    Scorpion7681, Nov 27, 2007
    Scorpion7681, Nov 27, 2007
    #4
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