It seems that after about 15 min my a/c just completly dies out. I let the car rest and when i turn it back on the a/c blows cold. I thought maybe it could be a loose wire. Any ideas on what else it could be??

Sounds like it may be a drainage problem, where the condensation is being blocked and icing up.

The only thing is that it doesn't lose a/c gradually. It completely dies out as if the compressor isn't working. Thats why i thought maybe it a loose connection wire. For example yesterday i drove it to the local wing stop, probably around 15 min and when i turned on the car it wouldn't throw cold air anymore. It sometimes happens when i'm driving also.

That is what Ron is telling you. AC systems have a capillary tube that senses the evaporator temperature. At the other end of that tube is a switch that sends power to the compressor. If the evaporator gets too cold or freezes up, the compressor will shut down until the evap temp is back within operating range.

Also, could be low pressure. Sometimes if the pressure is right on the edge it will run for a bit then shut off randomly. I chock it up to finicky pressure switches in these old systems.

I'm assuming that he has the aftermarket system and they generally don't have pressure switches.

The evaporator problem makes more sense. The one i have looks to be in pretty bad shape and might be faulty. Is there any way i can get to that capillary tube or do i need to replace the evaporator?

You might not be clear on the term 'evaporator'. It's located under the dash and the capillary tube sits between the fins of the evap to sense the temperature. You want it to shut off if the evap starts to freeze up. It will save your system. Which system do you have? Is you compressor upright or rotary? If it's the typical aftermarket system as there was no factory air in the US in a 72, it will look something like this. To get to the evaporator, you'll have to open the case. Make sure that drainage tube is not blocked because that could be the source of your problem as Ron earlier stated.

Thanks for the picture. I really don't know what type of a/c i have but it is after market. Thanks for the help.