First of all, I beg of anyone on here, for gods sake, never piece together an air conditioning system. The $1500 or so it cost for the aftermarket kits is worth it!

So, quick background. I bought my truck with a dealer installed AC in the cab. The type of AC that has the vents in the dash. P.O. removed everything under the hood including the condenser. I have installed from a factory AC junkyard truck, the condenser, dryer (will be replaced) and AC brackets. I have a new sanden compressor and expansion valve and will be converting to R134A. I am in the process of building new AC lines.

First, please correct me if I am wrong. The order of flow is....
Compressor>condenser>Dryer/receiver>Expansion valve>Evaporator>Suction side of compressor. The only reason I ask is that I have seen a few diagrams on the internets where the dryer is before the condenser.

Second, on the factory AC system there is what appears to be a one way valve (please see attached picture.) What I can't figure out is that is would block flow if my first assumption is correct. What is this thing? What am I missing? Should I or can I leave it out with the new sanden/R134A setup. For those who have installed an aftermarket kit, did they come with one? I can't find much info on this. Anything y'all can add would be huge help!

Thanks!!

 

I have factory ac on my 79 converted to 134a. I have replaced everything except hoses and evaporator at one point or another. My dryer is located after the condenser.

I have the same piece in the skinny hose exiting the dryer, I don't think it is a valve but more likely an adapter of some kind. I suppose it could be a check valve. The only valves I know of are the expansion valve located near evaporator and the service valves if you have them on the compressor.

 

Your order of flow is correct and the brass valve is a type of check valve. Ford used to allow you to remove some separate components of the AC system and remove them without losing the whole systems Freon. I've also heard it called a quick coupler.