Calvin Williams

I own a 77 chevy k10 I live in texas and its my only car so AC would be great the only recommendation i get is vintage air wich is 1400 and way out i my price range any suggestions would be great to help keep the truck cool this summer

oilcanhenry

You can change it over to use R-134A it you wish to do so. Let me know. I can likely help you out.

Calvin Williams

would you mind explaining how I would do that or the price range?

oilcanhenry

Well, you can buy an R-12 to R-134A conversion kit at most auto parts stores or online, They use fittings that are different then the R-12 systems, but they are designed to
replace your old fittings as they twist right in to your old R-12 refrigerant adapters, The cost is not that much. I will continue in my next post after this one is that is OK?

Calvin Williams

I looked into it and the problem is i would still need a working AC system wich i dont have so maybe if i replace all the compents i could do that

oilcanhenry

First off you need to find a retrofit kit from R-12 to R-134A. They cost around $12 to 15 dollare in the US.There will be two fittings, One for the low-pressure side and one for the high pressure side of your vehicle. Once you have installed these, you may have to purchase a new receiver-dryer unit, since it is likely in need of replacment anyhow., Those will be around $15-25 dollars on your vehicle. Next you will need to drain all the oil out of your compressor since that oil is not compatable with R-134A freon..You will be using PAG oil, but the system does not need much to operate properly. You can use something like ethanol or rubbing alchohol to get it all out of your compressor, the heart of an A/C system.. The retrofit kit should come with new o-rings that are compatable with the R-134A freon. Replace your old ones with these new parts.

oilcanhenry

How long would you think its been since your system was running properly? The only component of an A/C system that can be very difficult to replace is the evaporator under your dash. Everything else whould be easy on an older vehicle like yours. You can buy many used parts and devices cheaply at an automotive yard if you need to. I once put an entire A/C system in a car that had no A/C system at all, so since you do, this should be simple.

oilcanhenry

You will need to add PAG oil into your compressor after its cleaned out. 6 to 8 oz should plenty as your new R-134A will come with even more PAG oil. BTW, you should coat your seals in PAG oil before you install them. Once the system is tight comes the difficult part if you do not have or can borrow an A/C vacuum pump, You MUST get all the air OUT of the system, and have it hold at -30 PSI for an hour. You MAY be able to get it to half an hour, but only when its hot outside, not in wintertime. This will not only get rid of air, but it will boil out any water in the system. You can rent these vacuum pumps or they cost about 100 to 150 dollars at the auto store new

oilcanhenry

Once the system holds a negative pressure you will ready to use the new an A/C guage set to install the new R-134A. You will need two cans, maybe three to get it up to proper operating conditions. You must locate the low-pressure switch and bypass it so that your compressor is running as you add the new R-134a Freon to your system, using the low-side to allow the R-134A to enter your A/C system. Once you are done you may let it stabilize, and get the high and low reaidngs off the gague set. Your low-side readings should be in the 35-45 PSI range. The high sIde should be 150 to 220 PSI, since R-134A runs at higher pressures then R-12 did.

If you have any questions about all of this, feel free to ask me.