Last year I had to replace my 940's AC compressor, evap, low pressure line and drier. The only thing I needed the local shop for was to evacuate the system so that I could recharge it, but he did that too, r134 for $110. I wondered if I could have used my MityVac, and one of those $30 kits from the auto parts store. Yes, you can.

Last year before I understood the extent of my problems, I bought one of those AC recharge kits with the hose, and gage, and some r134. Those recharge kits won't work if there is air or moisture in the system (or a big leak!).

Recently, my son acquired an '89 BMW 525i that had been sitting around for a year after the PO had the timing belt break and needed new valves, camshaft, etc. Since, it had been sitting for nearly 2 years and the AC was not working, and I decided to try the Mityvac.

I manage to find a fitting that would go into the end of the hose where either the bottle or the gage would go, then I attached a 3/8's inch tygon hose to the fitting, and then to the Mityvac. The other end was attached to the low pressure port. You need to use the AC hose because you need to depress the valve in the fitting on the ac system. Then after about a 1,000 hand pumps later, I was able to establish and hold a 25 inch vacuum. Then I refilled, and Voila! - Cold Air!

I would not endorse this method if you already have a charge in your system, because there is no way to reclaim the freon and you'll end up releasing it to the atmosphere, so that not be very environmentally friendly. But, if you have no pressure, consider a MityVac.

Of course, there may be a flaw with this method, but it worked for me. Any thoughts?


Tom