Compressor going bad?

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by TallJoe, Jun 12, 2020.

  1. TallJoe

    TallJoe Road Train Member

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    I changed the air dryer filter cartridge 14 months ago. I guess it is time for it. I tried to change it myself but it is stuck....I could not twist it with the belt wrench. The whole dryer looked liked about to break off, gave up on it for today.

    The compressor starts slow , pumps up to a point - the gauge scale is not very precise - I think about 120 PSI and then, what puzzles me, I can't hear the air dryer purging and the gauge needle dropping to about 100 PSI. Pressure sort of hangs there all the time.
    I noticed compressor sweating oil lately it has over 1000 000 miles, not much but easy to notice. At the purging vent, some thick residue of dirt and oil... My guess I need new compressor and perhaps another air dryer too.
     
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  3. Rideandrepair

    Rideandrepair Road Train Member

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    The filters probably still good,for at least another year or more. Unless your compressors pumping a lot of oil. Filter catches oil too. Even new compressors pump at least a little, sometimes quite a bit. Depending on the cost of a whole new or reman drier, and the cost of a new, or reman spitter valve. I would at least replace the spitter valve, and the govenor. Keeping the old govenor as a spare. If filters stuck though, eventually you’ll need a whole new drier anyways. You can always replace compressor later. I guess there’s always the chance that filters bad now, if compressors pumping a lot of oil. I have changed filters, but AD9s are so cheap. Whole reman, is the same price as filter and spitter. I just change the whole thing. Yours may be expensive though. I’d be more concerned about the spitter and govenor. I replaced my Compressor 3-4 yrs yrs back, it was original, had 1.8 mil miles. It was pumping some oil, but still worked. Replaced air drier 8 mos ago. It was overdue. Filter was obviously full, and spitter started acting erratic, kind of like yours is doing. Eventually it started seeping, got worse, had to bypass filter. Replaced it with a reman, and a govenor. Set at 130. Good for another 4 yrs.
     
  4. pushbroom

    pushbroom Road Train Member

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    What style of air drier? AD-IP looks like a spin on but has a bolt that comes up from the bottom to hold the cartridge.
    AD-IS looks like a spin on and is one
     
  5. PE_T

    PE_T Road Train Member

    Yeah, your air compressor is probably bad. Check the hose that goes from your air compressor to the air dryer for signs of oil. Replacing your air dryer or filter may buy you some time, but I doubt it’s the cause. Mine had oil coming from the air compressor.

    As for removing the air dryer filter, first drain the air tank that is directly connected to it. My filter was also tough to remove. You want to use the belt wrench on the bottom or top of the filter. Avoid the center as you can break the filter. Give it a tug with the belt wrench on different positions of the filter to attempt to break it loose. For example, at 12 o’ clock, 4 o’ clock, and 8 o’ clock.
     
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  6. daf105paccar

    daf105paccar Road Train Member

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    I never run compressors that long.
    And airdryer cartrige...........2 a year.
    One just before winter,one after winter.
    They are cheap.


    I have a friend who runs a 14y old truck.
    Put a new compressor on when the truck was 8y old,regardless off miles.(truck had half a million miles then)
    2 cartridges a year.
    He has NOT replaced a single airvalve on that truck.
     
    Last edited: Jun 14, 2020
  7. TallJoe

    TallJoe Road Train Member

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    The end of story:
    After replacing the cartridge.., full of dirt and oil. The compressor was still weak pumping air. It could not go past the purging point.
    The compressor has been replaced (11- 12 years - 1200 000 miles on it). All is well now.
     
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