I've been posting about my unfortunate journey to replace the heater core on our 1993 Middle East 80. After cleaning and refurbishing the heater box and straightening the fins on the AC evaporator I've got things back together and it was time to vacuum the AC system to look for leaks in preparation for re-filling the system with refrigerant.
The only label under the hood says R12:
But when I took out the expansion valve on the evaporator, it was an R134A type expansion valve, and it looked new. So new I decided not to replace it.
But when I started hooking up hoses I found only one quick-connect. On the high pressure side of the AC compressor:
The other side, the low pressure side coming from the evaporator inside the cab, had what looks like an ordinary schrader valve. I was able to get the hose from the manifold set to screw onto it:
And just for fun here is a photo of me using my weird, antique lab pump to pull the vacuum:
My question to the assembled wisdom of this forum is what about the schrader-type valve on the low-pressure side. Is this something I should replace? Is this normal for a 1993? Should I just close up that side and refill only on the high-pressure side? I remember that the schrader valve was not working very well--when I took the dust cover off it, the refrigerant hissed out. The AC was working fine before I had to take the whole thing apart, but I'm suspicious of the schrader valve.
This is my very first sojourn into the world of AC. I have literally no prior experience to draw on. Any advice would be gratefully received!
The only label under the hood says R12:
But when I took out the expansion valve on the evaporator, it was an R134A type expansion valve, and it looked new. So new I decided not to replace it.
But when I started hooking up hoses I found only one quick-connect. On the high pressure side of the AC compressor:
The other side, the low pressure side coming from the evaporator inside the cab, had what looks like an ordinary schrader valve. I was able to get the hose from the manifold set to screw onto it:
And just for fun here is a photo of me using my weird, antique lab pump to pull the vacuum:
My question to the assembled wisdom of this forum is what about the schrader-type valve on the low-pressure side. Is this something I should replace? Is this normal for a 1993? Should I just close up that side and refill only on the high-pressure side? I remember that the schrader valve was not working very well--when I took the dust cover off it, the refrigerant hissed out. The AC was working fine before I had to take the whole thing apart, but I'm suspicious of the schrader valve.
This is my very first sojourn into the world of AC. I have literally no prior experience to draw on. Any advice would be gratefully received!