Charging The A/C On my 74 SII

[eyeluv2fish]

I have always charged my own A/C on my newer model cars. I have also done several conversions from R-12 to R-134A with nu hiccups...

Need help from someone with experience converting Scout A/C.

First - I need to figure out which is the low pressure side. I know that usually the low side is the one with the larger hose that gets cold when in operation. However, I bought one of those retrofit kits from Walmart (with the nipples and the R-134A/Oil Combination cannisters). I used it to charged what I thought was the low pressure side (the nipple on top) but it only took about 1/2 can before it read 60+ pounds and it still doesn't blow cold. Also, my compressor will go for several minutes sometimes before it kicks in. Then it may only run 3 seconds or less before the clutch disengages again. When this happens the blower on the inside also cuts out.

Did I charge the wrong side. Am I going to have problems using one of these retrofit kits or should I take it to a mechanic?

Any help is appreciated

 

[Philabuster]

Do NOT charge the discharge side with refrigerant! The refrigerant container can explode in your face from the overpressure.

Don't take this the wrong way, but if you don't know which side is the suction or discharge, you really should take it to a QUALIFIED mechanic.

 

[Steve Grant]

High side port on 134a systems has a larger outside diameter compared to the low side service port. When recharging a retrofitted system, charge to 75-80% system capacity. You might have a low charge. Do you own a manifold gauge set? They are nice to have so you can watch what the low side and the high side are doing. Did you pull a vacuum on the system?
Steve
1975 shortbed 4x4

 

[mesamonster]

I just got done doing this on my 78. I also ran into the problem of high preasure on the guage, it turned out to be the conector wouldn't stay on the nipple very good and I had to hold it in while I charged the system. The excessive preasure was a result of the coolant not being able to go through the poor connection at the nipple. I was only able to get the gauge that came with the kit to read like 25lbs. wich is supposed to be bottom level for a "good" charge. The compressor has an S on the case for the suction side. Mine was the top one.

 

[DavidWTravelallfan]

If you still have the YORK compressor look for a large "S" or "Suction" stamped somwhere near where the valve bolts to on the head of the compressor. On my travelall the valve on the top is the suction side.