What is this fitting?

[68RGR]

OK, truth be told, this is on my 73 F100 with A/C. But, it is also on a 69 F100 that I have access to. So, I'm hoping you guys can help.

The mystery fitting is on the end of the tube that comes from the A/C drier then goes through the radiator core support on my F100 with factory air. Formerly, a brass check valve had been connected to this fitting and a refrigerant hose was connected to the other side of the check valve. The other end of that hose has a tube o-ring fitting that connects to the bottom port of the expansion valve on the side nearest the engine. If you are familiar with this hose, it sort of looks like a fat clothes line running above the left side of the engine. At least, it does on my truck. It's the hose that always gets in the way of just about everything you try to do on that side.

The check valve will be eliminated and I want (need) to get a new hose fabricated. The hose size and expansion valve fitting aren't a problem.

But, what kind of fitting should the hose have to mate with the fitting in the photos? Hint - There was an o-ring in both ends of the check valve (both ends are female) and a 1/4 inch NPT nipple STARTS to thread into the check valve so it is similar in size to the mystery male fitting.

Anyone been down this road before?

I'll be happy to supply additional photos, measurements, etc.

Thanks

[mybros71]

These guys might be able to help.
http://www.oldairproducts.com/catalog/

I believe that fitting is olly used to attach a hose or rigid line to a block or other machined or fabricated part, not another hose or line. look at this picture and check out the (adapter?) between the E valve and the flexible hose. Maybe this helps?

[70_F100]

The original purpose for that "check valve" was to enable the system to be pre-charged so that refrigerant didn't have to be added at the assembly line. Hook everything up, bleed air at the compressor, and voila, it was done.

This also allowed the system to be split without discharging the refrigerant.

I doubt there is a replacement fitting available for just connecting a hose to that line.

IIRC, the "check valve" also included the sight glass which was used to verify that the system was fully charged with refrigerant.