AC Repair at home
 

I'm attempting a repair of the AC on my car. I have a set of gauges, a vacuum pump and a recovery tank. I am not going to spend the $500 on a recovery machine. The system has a full charge at this point, pressures indicate an issue with the control valve in the compressor. High low at idle, normal at RPM. Poor cooling at idle, normal at speed.

So, I put the tank in a cooler with ice and pulled a vacuum on it and my gauges before hooking it up to the car. Slowly opened the low side and then the high side to purge into the tank.

I'm down to about 25lbs still in the system and I can't get any lower. R134a is still available to the consumer and while I'm not going to get into a global warming debate, I don't like to contribute to the problem. I plan on taking the recovered R134a to a HVAC person and have them reclaim it.

I've thought of using the recovered R134a by purging the lines and connecting to the liquid side of the tank and using a sight glass, allow it to turn to a gas so i can see how much oil was pulled. I will put the tank on a scale so I can see how much I have pulled and then use cans to get it back to the proper level.

Wow, this got rather long... So, someone that knows what they are doing, where am I going wrong?

Call JUNGLE LAW

:clap:

You're getting pretty deep for your 1st attempt at auto AC.
You may have had a little air in the system?
If it's shy on the cold side at idle. I'd a just left it alone.
Obviously this is an older vehicle.
What exactly are you working on?
Scotty Kilmer has a lot of good vids on car ACs on YouTube.

This sounds like a bad scroll valve if its a scroll compressor. Its about a 30 buck part but needs to be completely evacuated and the requires an evac pump. The gas and liquid has to be evac'ed.
https://encrypted-tbn0.gstatic.com/i...ZAWu0&usqp=CAU

We have a winner. I watch Scotty Kilmer all the time, how many times has he quit YouTube?

Pulled a vacuum on it after I replaced the valve and gasket. Hardest part was getting my big mitts in there. Vacuum held so I pulled a vacuum on the gauges, lines, sight glass, etc. and then pulled the Freon from the storage tank. Put it in some warm water to bring the pressure up. Ended up adding about 12Oz to get close to the 1.09Kg required. I ended up letting a little out, system was down to about 22lbs (pressure @32 for R134a). Need dry ice or a machine to pull it down any further. Basic P=VT from high school.

Not so mysterious now... Don't open the high side to the gauges unless the system is empty and you are pulling a vacuum. Wear gloves and goggles just in case.

2006 Ford Freestyle; the low side hookup is in a stupid place...

The chances of getting all the refrigerant out of any A/C system without a recovery "machine" is low.
The only chance was to pull a vacuum on the recovery tank before putting any R134A in the tank and get it below 250 in. lbs. of mercury. I am sure you probably don't have a vacuum gauge.
If you take the R134a to a local HVAC person they are going to charge you a fee to accept this "freon".

You should charge the system with nitrogen to the top pressure the system is made and make sure it holds that pressure for at least an hour before adding new refrigerant to the system.

Thanks for the info; I ran my vacuum pump on the tank for an hour after I let the nitrogen out of it. It probably wasn't much different than just letting it out into the air however it helped me feel better about not contributing to 'Global Warming'. Given than every time someone gets into anything more serious than a fender bender, their AC condenser will get damaged and vent the refrigerant into the air, I made an attempt to capture as much as I could. I have a HVAC guy that I can probably get to recover it. I spent pretty good money having the evaporator coil replaced on my home AC. He used nitrogen to pressure the system and then we went hunting for leaks.

Blowing nice and cold in city traffic today and the pressures looked more like what the YouTube Ford videos on the valve issue show.

Had a 2007 Ford Five Hundred that had this problem watched some Ford Tech Makuloco youtube videos and he mentioned the scroll valve problems on ford and the cheap repair that a/c shops tend to not tell you about. A good friend who worked on my crew for years took over his dad's Auto shop. He told me to bring it in after hours and he would evac. I then removed 2 bolts that were a bitch to get at and replaced the valve. Took it back to the shop he flushed the system ran a pressure check refilled oil and recharged it. Worked like a charm after. The machine is so easy a trained monkey could run it. He didn't want to charge me a dime but I gave him 50 bucks and feel I got a great deal lol.

I watched a bunch of videos, got a sight glass and took a look at the refrigerant. It was clear and everything looked like the acceptable pictures. I understand why shops don't want to fix things this way, that AC equipment isn't cheap and no one really fixes anything these days. We are conditioned to just throw it away and buy new. Plus if the compressor goes out after replacing the valve, they are going to have to cover the cost of it. If this repair didn't work, I was going to replace the compressor anyways. I might not ever use the pump and gauges again however it's nice to know how things work and it's still fun to tinker with something as long as you respect that it can bite you.

Yeah, those two bolts ere a PITA. Had to use a wrench on the top one and the bottom one is so cramped that I was lucky to get a single click on the ratchet.