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Re: Check list for A/C fixing Posted by JerseySaab [Email] (#666) [Profile/Gallery] (more from JerseySaab) on Tue, 8 Jul 2014 11:06:27 In Reply to: Check list for A/C fixing, CBS [Profile/Gallery] , Tue, 8 Jul 2014 09:46:04 Members do not see ads below this line. - Help Keep This Site Online - Signup |
One quick test you can do for the compressor is to turn it by hand, it should turn smoothly with no bad noises. If it binds up you've got a problem. (If it turns smoothly that's not really a guarantee as there might be leaky seals or other issues that won't show up as a mechanical binding, but if it does bind you know it's bad.) If the compressor has failed internally it likely has sent debris into the system and you'll need to flush it out.
Is the system already empty? If it has R12 and is just low you can use an electronic leak detector to find where it's leaking out. Back in the day we used to use a propane torch with a probe to find leaks (the flame would react to the presence of R12) but I have not seen one of those setups in a long time. Another approach of course is to charge in some dye and use a UV light to check for leaks.
Envirosafe works great, I have been running it in my C900 since repairing the AC system years ago and use it on some old "Brand X" cars as well. However if you use this or any other non-standard refrigerant you are committing to servicing the system yourself as the vast majority of shops will not want to touch it.
You will need a vacuum pump to pull air and moisture out of the system before charging in the refrigerant. You can make one out of an old air conditioner or refrigerator compressor (lots of info online for doing this), or Harbor Freight has one that works well that you can usually buy for under $100. There are also air-powered pumps for cheap that some report success with, though you need a decent air compressor to make those work.
You don't normally need to add oil if all you do is evacuate the system since most of it stays put. You do need to add oil if you replace components. There are rules of thumb for how much to add when replacing a hose, condenser, evaporator, etc. Note that you are really supposed to change the drier any time the system is opened up.
If your hoses are original you should probably replace them and the drier. What I did on mine was to replace the hoses, drier, and the expansion valve. I have had very bad luck with aftermarket expansion valves. The first one I tried on my C900 was bad and I had to change it out for another. I went through a couple of bad ones on my 9000 and wound up just cleaning the original valve and putting it back.
Bear in mind that Envirosafe is flammable, so use appropriate safety precautions while working with it. (No smoking!)
The C900 AC system is pretty basic, not really too much different than what you might find on a 1960s-vintage U.S. car.
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