AC lines standard/metric

Discussion in 'Tech Discussion' started by yevgenievich, Jun 5, 2018.

  1. yevgenievich

    yevgenievich Full Access Member

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    Generally when there are notches on the fittings it is an indication of them being metric. I am going to evacuate system for verification next week to verify but wondering if anybody has confirmation that up to 91 GM did use all standard fittings in ac lines. My lines have notches, but I believe it should have standard threads and so does one of the ac places I have called.

    In short, I was going to order some adapters so I can have minimal down time, but these notches threw me off. Changes my down time by few days just to verify the thread size.
     
  2. 75gmck25

    75gmck25 Full Access Member

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    I don't know the answer for a '91 Sub, but for older vehicles with O-ring fittings, the sizes are SAE. However, this is usually how they are listed.
    #12 - 3/4"
    #10 - 5/8"
    #8 - 1/2"
    #6 - 3/8"
    So when you research something like a condenser or compressor it will be listed as having a #8 and a #10 fitting size.

    Bruce
     
  3. yevgenievich

    yevgenievich Full Access Member

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    That is what my understanding was, but sometimes metric threada are used and the guys making hoses always identify those fittings due to the notches. My hoses have them, which created confusion. I went ahead with ordering sae adapter as the drier also states sae fittings.

    tmp_25595-IMG_20180603_1328221495084070.jpg
     
  4. bucket

    bucket Super Moderator Staff Member

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    I thought the notches were simply to prevent thread galling?

    Eh, nevermind. I overlooked the picture.
     
  5. yevgenievich

    yevgenievich Full Access Member

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    Verified to be standard thread. Do not know why this set of hoses has metric indicators.
     

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