does anyone know how to change the whole ac compressor. im trying to switch one from my old truck to my new one. i know i have to drain the system somehow but im not sure how to do that and i cant find it anywhere thanks

 

Need a machine to evacuate the system, then just swap the compressor, go back to where you had the system evac'ed, and have them recharge it. (which will mean pulling a vacuum on it again, and then re-filling with oil/refrigerant.)

 

Oh ok. It's not something I can do at home then? What if I just do the pulley bypass. Do I still need to drain it first?

 

and how much do they usally charge to do that?

 

No you dont need to drain the system to bypass the ac compressor.

You'll have to call some places in your area and ask.

 

oh ok i might just bypass is for now till i can afford to do a new compressor and have them charge it. so i can just unbolt the compressor and unplug it and nothing will happen?

 

Once the system is evacuated, it will make a rude noise when you take off the lines, but, that's about it. Four bolts, a belt, the lines, and an electrical connector, and off it comes.

 

I assumed by "bypassing" you meant just remove the belt from the compressor. If you want to actually remove the compressor, you will have to drain it first. Now, many years ago in the days of R12, it wass environmentally "unfriendly" to let that stuff vent to atmosphere (not that I ever did that), so they came up with the R134, it was supposed to be "safe" for the environment but they still wanted you to properly "evacuate" the system, i.e. recover the R134. I'm not by any means a proponent of this, but I have bled AC systems to atmosphere. Probably a tree hugger is going to shoot me now. You can drain the system and remove the compressor for now, but know that, by opening the system, you will get moisture inside. AC systems and moisture do not get along. When you do go to reinstall the compressor you will probably need to replace the drier and orifice tube as well as getting the system evacuated.

One question though, why are you trying to swap compressors in the first place?

 

I have a truck that I'm using for parts and the compressor was still good in it so I was just going to swap and stay on the cheap side. I removed it and let it drain slowly from the lines and hooked up the newer one and got it all done in about an hr and a half. The old one was making some horable noises so I figured it was easy to just switch them. I'm going to get it vaced by a shop as soon as I have some cash.

 

I have replaced compressors before and just bought a couple cans of refrigerant from wallyworld and refilled the system without pulling a vacuum first. Never had an issue doing that and the ac worked fine and blew cold afterward. The key is to limit the amount of time the system is open.