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There's this tiny lil vac hose on my firewall..what's it go to?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by PetaKane, Oct 18, 2002.

  1. PetaKane

    PetaKane 1/2 ton status

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    There\'s this tiny lil vac hose on my firewall..what\'s it go to?

    It starts on the far driverside fenderwell, comes from a thing that looks like a ball to me. I'd say it's a 1/4" hose from there and it goes about halfway across the firewall where it has a T fitting and one of the vac holes of the t is not connected to anything. The other vac hole turns into an even smaller hose that runs into the cab through a grommet. Sorry if this is confusing but does anyone know what this hose is?
     
  2. 4x4k20

    4x4k20 1/2 ton status

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    Re: There\'s this tiny lil vac hose on my firewall..what\'s it go to?

    its the vacum supply for using you heater or a/c it controls the duct work under your dash. defrost control . heat. vent etc.
     
  3. wrathORC

    wrathORC 1/2 ton status

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    Re: There\'s this tiny lil vac hose on my firewall..what\'s it go to?

    The round thing about the size of a grapefruit is a vacuum reservoir. The hose goes all the way across and goes into the cab to operate your vents. I'm pretty sure the "T" on mine goes to the manifold but I'd have to look.
     
  4. Z3PR

    Z3PR Banned

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    Re: There\'s this tiny lil vac hose on my firewall..what\'s it go to?

    Cruse controle maybe ???
     
  5. loudnowlouder

    loudnowlouder 1/2 ton status

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    Re: There\'s this tiny lil vac hose on my firewall..what\'s it go to?

    i agree completely with wrath..
    reservoir and tubes that go thru the firewal are for the heater, controls, the flaps in the box under your dash are operated on vacuum...
    thats the first thing i disconnect when i'm having a vacuum leak, makes finding leaks much easier, i just forget to put them back on, it never seems to be plugged in when i need heat
     
  6. PetaKane

    PetaKane 1/2 ton status

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    Re: There\'s this tiny lil vac hose on my firewall..what\'s it go to?

    I got me a new Autometer vacuum gauge. Is this a bad place to tap into vacuum since it's coming from a reservoir? I'd tap into the big hose from the manifold, but it's huge compared to the little bitty hose for the gauge.
     
  7. wrathORC

    wrathORC 1/2 ton status

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    Re: There\'s this tiny lil vac hose on my firewall..what\'s it go to?

    Put a big "T" with a little offshoot for the gauge. They do exist, they're just hard to find. Ideally, you want manifold vacuum and not port vacuum also so don't hook it up to the carburetor.

    How much did you pay for your gauge and where did you get it? I want one but I'm cheap.

    I just paid $6.50 for a large brass one with a 20% discount. That's rape where I'm from. We can get the brass ones for ~$3.00 in downstate Michigan and there is a large selection.
     

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