I have collected some AC stuff over the years – AC testing kit, the usual AC top up kits and a vacuum pump.
This is my setup to vacuum down the system via the connection on the high pressure side. It will allow vacuuming on both sides of the AC pump – both the condenser and the evaporator and dryer.
I’m using the low pressure side gauge as it shows vacuum to 30 #s. Unfortunately it would not hold it’s vacuum, but slowly dropped.
It’s impossible to hear air leaking into the system so I connected up a bottle of R22a and put a small quantity of gas into the system. I actually held the bottle upside down to get the liquid refrigerant into the system.
I then went over all the connections and sprayed them with a little soapy water. I found a spot where bubbles came out under the cap on the low side connection. I took the cap off and replaced the schrader valve.
I then released the gas and vacuumed the system for 45 minutes. After that I let the system stand for an hour. The needle dropped a bit, but I suspect that was caused by my closing (releasing pressure) and then opening the valves to take the pressure reading.
As a last step I again charged the system with a little refrigerant. I’d rather have the system lose a bit of gas rather than have it vacuum in air and moisture. I won’t be charging the system until some time later this summer when I’ve got all the bugs out of the new engine/trans and the temperature gets into the 70-80 degree range.
Next: Waiting for the seats to arrive