The old '87 GL 4 wheeler wagon is blowing warm air. The AC compressor seemed to be kicking in normally, so I bought the kit at Kragen that converts the nipple to R-134. While the stuff was going in, it was also leaking out of a switch (4 wires) by the reciever/drier. I removed the switch, and some refrigerant did come out, de-presurizing the system completely.

 

So today I found a used switch at a wrecking yard. (New ones cost $80). I installed it and now the compressor won't kick in. My guess is the system must have some pressure in there to allow the compressor to work.

 

Anybody care to tackle this one?

 

Steve

 

 

 

I

Yes, the system does indeed need to be pressurized to work. Make sure the system is 100% empty beacause mixing R12 and R134 will rot your seals!

 

Once you've verified everything, start the car, turn the AC on max, and start adding refrigerant through the low side service port (the one by the battery). It'll suck it in and eventually the compressor will kick back on. 2 cans of pre-mixed refrigerant and oil charge do pretty well for a Subaru.

System needs to be more than empty; I pulled a vacuum on mine overnight before finally adding the R134a.

Neither Chilton's nor Hayne's manuals tell you which side is the low side. A search here a little while back turned up nothing (I bought one of those kits too, it's high 90s here). Good information to have in the archives.

Having any air in the system will severely diminish the ability of the A/c system to work. If you open the system to atmosphere, then close it back up and then just put the refrigerent in there, you will have A LOT of air in there too. A/c systems don't like to have air in them. To get a good working system you will need to put the system into a deep vacume for at least 2 hours. Then add your refrigerent. The best way to do it is to turn on the A/c, with the engine running, then start putting it in the low side, once the pressure gets up high enough, the compressor will kick in, and it will suck the rest of the can out. If memory serves me correctly, a Soob uses about 18oz of R134a. Remember, 135a is more dense than R12, so you need less of it to fill the system up.

 

I don't really condone untrained people to work on A/c systems (as most of the time I'm the one that has to fix their mess ups.) But this should help you out with getting your system working.

 

And remember, you must use a can of R12 to 134a retrofit kit. If not, the mixing of 12 and 134 without the proper chemicals to make them compatable, then it can have way more distasterous effects than just rotted seals.

there be a chemicals to make R12 and R134a compatable?

How are you guys applying vacuum to the system? And from where?

You need a vacuum pump and hoses to hook it into the system; hoses preferably with the guages for checking the system. Sorry but I don't know any other way to do that; luckily we do a little bit of refrigeration work in the shop I work in and I have access to the items I need.

How are you guys applying vacuum to the system? And from where?