Rebuilding AC this spring
- Thread starter Zeus1978
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Flush the hell out of anything you don't replace.
Put a little oil (Mineral oil for R12, PAG or POE oil for R134) in the accumulator to soak that sock, I also put a little in the evaporator and condenser, and just a few drops in the compressor and worked that around by manually turning the compressor.
If using R134, about 75-80% maximum of the amount of R12 you would normally use.
Use the green 134 O-rings/seals where applicable if using R134.
Once everything is bolted together, vacuum suck the crap out of it and make sure it holds for a long time. Don't just suck it down and call it a day. You want to flash off every bit of moisture and dry the system. Moisture and R134 = hydrofluoric acid. Probably not even close to being good for your system.
You don't have to, but you may want to think about putting in a variable orifice for R134. Again, not necessary, but the variable one can adjust for the pressure changes (higher pressures with 134 over R12.
Go slow and take your time. Ensure every leak is chased down and eliminated. Don't overfill the system. DON'T try to add straight liquid refrigerant if the engine is running and system is operating. If the system cycles with part throttle, you probably haven't added enough.
Best to weigh the cylinder and add the calculated amount. You don't absolutely have to, but if not, use a thermometer in the vents to help get your air chilling at a/c idle speeds.
Put a little oil (Mineral oil for R12, PAG or POE oil for R134) in the accumulator to soak that sock, I also put a little in the evaporator and condenser, and just a few drops in the compressor and worked that around by manually turning the compressor.
If using R134, about 75-80% maximum of the amount of R12 you would normally use.
Use the green 134 O-rings/seals where applicable if using R134.
Once everything is bolted together, vacuum suck the crap out of it and make sure it holds for a long time. Don't just suck it down and call it a day. You want to flash off every bit of moisture and dry the system. Moisture and R134 = hydrofluoric acid. Probably not even close to being good for your system.
You don't have to, but you may want to think about putting in a variable orifice for R134. Again, not necessary, but the variable one can adjust for the pressure changes (higher pressures with 134 over R12.
Go slow and take your time. Ensure every leak is chased down and eliminated. Don't overfill the system. DON'T try to add straight liquid refrigerant if the engine is running and system is operating. If the system cycles with part throttle, you probably haven't added enough.
Best to weigh the cylinder and add the calculated amount. You don't absolutely have to, but if not, use a thermometer in the vents to help get your air chilling at a/c idle speeds.
I just gutted my whole A/C system if you need any parts. I don't plan on reinstalling it, so let me know.
Rebuilding the A/C system is fairly easy in a G-body. IF you're using mostly new parts and not replacing the evaporator. That's where a huge PITA will be. Also, if you use the newer style condenser you will likely need to modify the mounting a bit from stock because the stock unit fits a little different than a replacement. Which is usually a cross flow type. Make sure you lube up the seals/O-rings with the proper oil and test fit everything first before grinking things down.
Just watch your torque. You're working with aluminum threads mostly, so be careful.
Just watch your torque. You're working with aluminum threads mostly, so be careful.
I gotta get my lazy butt out in the garage and replace the Evap Core on the El Camino. Summer is just around the corner here in Phoenix. I'm lucky I still have a good supply of R-12 I bought years ago.
HVAC system hold 10 ounces of oil total so the rule of thumb is 6 in the accumulator as it is the holding area, 1.5 in condenser and evaporator core and the rest in the lines. Make sure you drain the compressor and turn over manually. Make sure you evacuate with an electric vacuum pump with a recent oil change. Just because a vacuum pump reads 30 on the gauge does not mean it is working. If you want me to expand let me know
The only advice I have is open whatever replacement parts you get and confirm they will fit before the return window expires.
If I want you to expand, I'll give you a box of donuts and a venti mochaccino. 🙂
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