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Why are there differential breathers??

Discussion in '80-Series Tech' started by erics_bruisers, Sep 18, 2003.

  1. erics_bruisers

    erics_bruisers

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    I understand that there's a giant sucking sound from the diffs as they work, taking in air, and if the breathers are plugged, the diffs will suck in grease from the knuckles --

    -- but, theoretically, why do the diffs suck in air as they work? Also, where does this air go?? It must be exhausted somewhere --

    -- thanks --

    eric
     
  2. cruiserman

    cruiserman

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    Expansion and contraction due to heating and cooling, respectively. The diff gets pretty hot while driving.
     
  3. yomama

    yomama

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    It also has to do with rotation in the axle. Did you know your hard drive in your PC has a vent? Not to expell heat, but to more less equalize the pressure do to the rotation of the platters.

    Yomama
     
  4. erics_bruisers

    erics_bruisers

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    [quote author=yomama link=board=2;threadid=5413;start=msg42646#msg42646 date=1063912399]
    It also has to do with rotation in the axle. Did you know your hard drive in your PC has a vent? Not to expell heat, but to more less equalize the pressure do to the rotation of the platters.

    Yomama
    [/quote]

    so air is inhaled and exhausted through the breathers?? that makes sense, from what you're saying --
     
  5. yomama

    yomama

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    That is my take on it...Otherwise they probably would have called it an exhaust or intake :rolleyes:

    Yomama
     
  6. landtoy80

    landtoy80

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    [quote author=yomama link=board=2;threadid=5413;start=msg42646#msg42646 date=1063912399]
    It also has to do with rotation in the axle. Did you know your hard drive in your PC has a vent? Not to expell heat, but to more less equalize the pressure do to the rotation of the platters.

    Yomama
    [/quote]

    No, the reason for the vent on the hard drive is, when you add data to the drive it takes up room. When you get a new hard drive there is room to spare. As you fill it up the air has to go somewhere so its vented out the vent :slap:
     
  7. IdahoDoug

    IdahoDoug

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    Driving a warm/hot diff into a cool/cold stream causes rapid contraction of the air inside. This vacuum would draw water into the differentials through the seals each time it happened here, or in ordinary driving and hitting a puddle. The vent allows the diff to equalize its internal pressure when this normal heating and cooling takes place. Heat up your lunch in a tupperware container with the microwave and put it in the fridge with the lid back on. About 10 minutes later, the container will be severely distorted for a perfect example.

    On the 80, it's my opinion the front differential breather should have its flapper valve removed and the breather hose extended up into the engine bay to prevent the constant pumping of gear oil and birf grease back and forth. Especially if you wheel. The flapper clogs WAY too easily and was a poor design.

    IdahoDoug
     
  8. MTNRAT

    MTNRAT

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