Dreaded air dryer problem...

Discussion in 'Mack Forum' started by Dave1837, Mar 6, 2021.

  1. Dave1837

    Dave1837 Road Train Member

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    We've all had to sleep next to a truck with a repetitive air dryer pop off. It's enough to drive anyone crazy. I just moved into a 2015 Mack Pinnacle and it seems as if the air compressor is continuously running. Nobody is in the shop today (Saturday) for me to ask, so I was just wondering if this is a common issue. Also, when it pops off, it's not just a "pshh" sound, it's more like a long "whoooooosh". Very loud and obnoxious. I don't notice the air pressure dropping by looking at the gauges and don't hear any external air leaks, and it occurs both bobtail and with a trailer connected
     
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  3. Alpha Bandit

    Alpha Bandit Bobtail Member

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    Does the dryer continue releasing air slowly after the "whoosh"?
    It sounds like it may need new air dryer cartridge or a new air dryer. In some cases if there is a lot of oil in the dryer, a new compressor. It's a sign of the compressor going out. It's good for the problem to get fixed if your air compressor is running constantly, because its gonna run out of life quicker. Hope that helps
     
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  4. bonder45

    bonder45 Road Train Member

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    Yeah, replace the air dryer "Filter" should be a spin off - few bolts.
     
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  5. Dave1837

    Dave1837 Road Train Member

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    I let the truck idle for a bit and listened for leaks. There is no air leaking after it "pops" off, but the compressor stops, then kicks back on about a minute later even though the pressure barely dropped
     
  6. AModelCat

    AModelCat Road Train Member

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    If primary and secondary aren't leaking down, likely a leak in the wet tank or governor signal line.
     
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  7. Dave1837

    Dave1837 Road Train Member

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    What is a wet tank?
     
  8. AModelCat

    AModelCat Road Train Member

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    The one the air dryer fills first. Primary and secondary get filled from that tank. There should be 1 way check valves to prevent primary and secondary air from draining back into the wet tank.
     
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  9. Dave1837

    Dave1837 Road Train Member

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    Is that why there's 3 cans in between the steps? Screenshot_20210306-153339.png
     
  10. supersnackbar

    supersnackbar Road Train Member

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    The wet tank on a Pinnacle was the black tank directly under the drivers side floorboard, sitting longways above the battery box.

    Sounds more like a bad air governor...and unless you like getting dirty, it needs a shop to replace it.
     
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  11. Dave1837

    Dave1837 Road Train Member

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    Yeah repairing it is way out of my league. I just like to have all my ducks in a row on the write up slip so the mechanics don't think I'm an idiot lol
     
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