A/C Thread Sizes

[ehjorten]

What are the two different thread sizes on our A/C systems? I need to order fittings to make custom A/C hoses for my 1991 V3500 and I am not certain the size and thread pitch. I think they are 7/8"-14 and 3/4"-16, but I am not certain.

[ehjorten]

So I am thinking that my 1991 V3500 has metric threads on the accumulator...M27x2.0 for the connection to the low-side suction line to the compressor, and I am guessing that the discharge line to the condenser is a M20x1.5, but I am unsure because I don't have any nuts to check that this is the case.
The LS conversion Sanden SD7H15 compresser has 3/4"-16 and 7/8"-14 connections.

[VileZambonie]

If you are making your own, you can order beadlock fitting assortment kits really cheap on eBay. I had a hard time finding the one at the accumulator, so I cut the hose off of the oe one, and crimped a new shell to the stock fitting. Look here too https://coldhose.com/collections/fittings

[Scott91370]

Here is what I found but cannot confirm it 100% (and it is for the 85).
Compressor to condenser top- #8 to #8 O-ring - DISCHARGE side of compressor
Condenser to evaporator bottom #12 O-ring to #6 O-ring - Contains Orifice Tube
Drier is mounted on the upper 3/4" fitting on the evaporator - no hose
Drier to Compressor #10 to #12 (3/4") o-ring - SUCTION side of compressor