R12 and I’m Tired of Sweatin’

[44SAA]

I just completed a heater core swap on the ol 1980 and it can blow some serious hot air. Time to work on the defunct AC system. PO said AC has a leak(s). When I bought the truck the PO gave me about 20lbs of R12- thus I have zero interest in R134 conversion. Truck blows hard but only ambient temp.
Questions:
Is it possible to perform a leak check without charging w R12 first?
Can shops still leak check for a R12 system?

Thank you

[Ziegelsteinfaust]

Yes use nitrogen which is about a $20 refill if you own the bottle already. I do commercial ac, and my gauges fit old R12 fittings.

I would pressurize the system to 100 Psi, and use spray leak detector. It is most likely the hoses so I would replace the first as a way to proof check the work.

[Jaysonb]

I would put some new hoses on, and then replace all of the old o-rings, install a new dryer and oriface tube while you have it apart, then just test it for leaks by putting in vacuum and see if it holds. That would be pretty cheap, and easy.

[homemade87]

I would agree with the vacuum . Easier for the diy and easier to come by a pump. First I would pull vacuum and see if it leaks pretty quick . If not let it sit over night and see what it does . As stated above it would be a good ideal to change all the hoses and other parts . Then check it again with vacuum and see what it does .

I like to check it first and after to know I fixed the problem . If not you just don't know for sure .

All this assuming the compressor is good . If you get the filter out and full of black stuff and crud you will need to flush the condenser and evaporator as well .

[4x4k30]

Originally Posted by 44SAA

I just completed a heater core swap on the ol 1980 and it can blow some serious hot air. Time to work on the defunct AC system. PO said AC has a leak(s). When I bought the truck the PO gave me about 20lbs of R12- thus I have zero interest in R134 conversion. Truck blows hard but only ambient temp.
Questions:
Is it possible to perform a leak check without charging w R12 first?
Can shops still leak check for a R12 system?

Thank you

sell that r12 and buy r134 . r12 is $30-$35 a can 20lbs $600 to$700. and the r12 you are supposed to be licensed to use it.

[Dead Parrot]

Depending on how long it wasn't used, possible the seals in the compressor are shot. Common fail is the hose from the compressor to the condensing coil in front of the radiator. Gets both highest pressure and hottest temps.

Be worth getting a gauge and checking for pressure before doing anything. Might get very lucky and just need a fuse or a top off with R-12.

Also from experience, make sure ALL of the green wire connectors are pressed tight on the AC system. They can get bumped off while changing the heater core, which will keep the compressor from getting power.

If that doesn't work out, talk to an AC shop about trading your R-12 for a full AC repair job on your truck.

[68longhorn]

Vacuum check is best first. Vacuum the system for 45 minutes, the system should vacuum down to -28- -30. If the system holds for a couple hours there are no leaks. If it loses vacuum filling with nitrogen is a good substitute that is thinner then the refrigerant so the leaks are more pronounced. You can use soapy water like checking a tire to check the system.

I think the biggest challenge may be finding a shop to charge the system with R12. A lot of places don't touch it anymore and you need to be licensed to perform repairs. Worst case scenario you need to convert to r134. I changed my system over when my compressor went bad in 2010 or 2011. All I did was screw the adapter fittings onto my charge port and recharge the system. I didn't change oils, evaporator or condenser and there is no noticeable difference in performance from r12 to r134. I live in SW Florida and my AC gets used almost year round.

[44SAA]

Great ideas- thank y’all