Air pressure not building

Discussion in 'Trucks [ Eighteen Wheelers ]' started by Bigray, Jul 8, 2009.

  1. Bigray

    Bigray Road Train Member

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    started up the truck yest. air pressure built up and drove it too the store, turned off truck and when i came back out, press. had bled down and would not build back up.

    any suggestions on what too check ?
     
  2. PharmPhail

    PharmPhail Road Train Member

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    You're bobtailing? Won't build with the yellow in or out?

    Usually you follow the sound. It may be hard to find with the truck running. If it won't build at ALL than I would suspect the air compressor itself. :biggrin_25516:
     
  3. Bigray

    Bigray Road Train Member

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    yeah, i am leaning towards the compressor.

    gonna go pull off th line and see if air is coming out of it ...
     
  4. 112racing

    112racing Road Train Member

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  5. Bigray

    Bigray Road Train Member

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    PULLED the line off the top of comp. and def. had air coming out of it.
     
  6. Coonass

    Coonass "Freshy Fresh"

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    The piece that opens to bleed off air I'd check that.

    I've had one open to bleed off air and it would not close back.
    I had to manually close it.
     
  7. Bigray

    Bigray Road Train Member

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    that sounds like what is is doing, like i stated did fine yest. morning. but then it wounld'nt build after i got back in ut
     
  8. Coonass

    Coonass "Freshy Fresh"

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    Can you hear air coming out somewhere when the truck is running??
     
  9. pullingtrucker

    pullingtrucker Road Train Member

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    The part Coonass is refering to is called a purge valve. They do go bad, but usually in the winter or cold weather due to freezing. I would check the governor. The governor will either be mounted on the side of the air compressor or air dryer. You can try tapping on the side of it to see if the truck will build air. I have had the unloader valve in the compressor go bad, but not very often. They are easy to replace, just a little length to explain. I don't want to sound like I'm blowing anybody off, but Bendix has a great online library full of manuals that are free. They even have a basic airbrake handbook for newbies that I think every new driver should have to read. Let us know if ya need more help.
     
    jacksd3 and 7mouths2feed Thank this.
  10. Bigray

    Bigray Road Train Member

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    okay, here is the latest, went to NAPA and purchased a regulator /installed it.

    works like a chammp...

    TY all for all your help/comments....
     
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