Originally Posted by ROLLGUY

As far as I know they are metric, and my local hose guy did not have anything but SAE. I have done the low side hose going into the cab by welding on a #12 barb to the factory fitting. The high side hose going into the cabin (blue) is made of some different kind of material that does not wear out like the larger rubber hoses, and in my opinion does not need to be replaced unless damaged in some way.