Air dryer shooting every 20 seconds

Discussion in 'Trucks [ Eighteen Wheelers ]' started by Antonovich, Nov 15, 2019.

  1. Antonovich

    Antonovich Light Load Member

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    I've replaced my air dryer about 5 months ago. It worked fine throughout the summer but now in the cold it started purging every 20 seconds or so. It's either the fluttering purge or like an air cannon going off. The fluttering is not a problem but the shooting definitely is when I'm trying to sleep. Not sure if it's just a crappy air dryer off of eBay or there is a bigger issue.

    It's the standard AD9 type of air dryer. I did not replace the compressor nor the governor. There doesn't appear to be an immediate air leak but my primary tank would loose about 40 psi overnight with engine off. Secondary would loose only about 10psi.
     
  2. starmac

    starmac Road Train Member

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    That amount of air loss, unless it is losing more when you have your valves pushed in to run, will not cause any trouble. I am thinking you need to put a kit in the drier.
    Just curious but is that ebay drier original or a knockoff?
     
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  3. Antonovich

    Antonovich Light Load Member

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    No idea if it's a knockoff or not. As I remember, there are no markings on it. I'm guessing it is a knock off. What do you mean by kit? A new purge valve?

    Forgot to mention, the cutoff pressure is set to 130psi and was always that, if that helps.
     
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  4. baha

    baha Road Train Member

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    If its only dropping a few Lps. and comp. is turning on then spitting over and over, You can put a new air gov. on and that should fix it?
     
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  5. magoo68

    magoo68 Road Train Member

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    Check signal line to governor it probably had a pin hole or loose fitting . I suspect your air doesn’t drop at all before compressor kicks in
     
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  6. Star4900

    Star4900 Medium Load Member

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    Sounds like the purge valve is froze or failed. Just had to replace the one on my Star, was doing the same thing. Air dryer cartridge was still fairly new and fine. Just goes to show, even on new trucks, stuff can still fail.
     
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  7. 6wheeler

    6wheeler Road Train Member

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    That's it. Purge valve. There built to fail every 6 months or less.
     
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  8. Antonovich

    Antonovich Light Load Member

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    If the purge valve failed wouldn't it just stay open and purge whatever air was coming into the system? I had that before. Actually my air dryer crapped out on the second day after I bought the truck. It looked original, like a rusted out hunk of ####. Had a Love's mechanic do a bypass but bought a new dryer anyway for the winter. Maybe it is just a coincidence that it happened when it got cold and it's another issue, maybe it does have something to do with outside temperature.

    It doesn't shoot all the time. Every other time it purges, it simply flutters, and on rare occasions it purges with a barely audible puff.

    My air compressor looks original, in that it looks like a rusted piece of crap. So I'd guess the governor is also original. It's cheap enough, guess I'll try to change that first and see if it works. Are governors universal or are they specific to the engine or air dryer?
     
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  9. Antonovich

    Antonovich Light Load Member

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    So I just noticed something, my compressor airs up to about 128 psi, I hear the purge, but my pressure doesn't go down at all.
     
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  10. starmac

    starmac Road Train Member

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    It is not suppose to go down unless you use some air, but it sounds like you may have a small leak in the line going to the governor, unless the governor has been adjusted to go that high.
     
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