AC lines standard/metric

[yevgenievich]

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.

 

[75gmck25]

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

 

[yevgenievich]

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.

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

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[bucket]

I thought the notches were simply to prevent thread galling?

Eh, nevermind. I overlooked the picture.

 

[yevgenievich]

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