Does the vacuum on the AC need to be a slow 1? Local Autozones around here do not offer it on there loan list, like i have saw some people say.. I know several people working on there AC's and want to pull a vacuum. I was curious if i could make a pump. I have a couple old Ford AC pumps. They suck from 1 side and blow on the other. I have a couple electric motors. I could mount them on a 2x6 and hook to the suction side. but it would be quick , prolly 10 or 15 seconds would have it down to 30. I like making my own stuff like that but didn't know if there was a reason that it needed to be a slow vacuum?

 

If you want to slow it down, you could add a valve on the suction side of the compressor you use. Start with the valve fully open when you fire up your compressor, as you slowly close off the valve, you'll slowly lower the pressure in your AC system.

Are you sure that you can get a low enough pressure to evacuate the AC system with the compressor you're going to be using?

 

Here is the vacuum pump I used on my a/c. -clicky- You can't beat the price (10 bucks). It pulled my system down to approximately 25 inhg in less than 60 seconds.

 

that air operated vacuum pump is definetly the cheapest way to go. and it does work. need a pretty decent shop compressor to run it though, and it aint real quite.

 

OK , cool.. I had no idea that existed .. Cheapest 1 i had seen was 100 bucks.. Yours is definitely the way to go!!

 

you can rent one from autozone for free...You just need to pay the deposite.

 

inches in mercury, inhg, does not mean you have pulled a good vacuum, you need a micron guage to properly do it, and that means holding a vacuum at less than 500 microns for at least 15 minutes after the pump is shut off. but anyway, i've pulled vacuums with a compressor out of a fridge.

 

I purchased one of those harbor freight air operated vacuum pumps, actually all it is is a little venturi in a big package. I purchased one to try when I was vacuum forming Lexan windshields for recumbent bicycles. It worked marginally. 28.3 inhg is equivalent to 13.90psia. What pressure are you trying to reach? Take a look at McMaster Carr (click here) and you can pick a wide range of options. You need to know what your air compressor specifications are with respect to volumetric flow rate at a given pressure. With that information, you can find a venturi that will fit your needs.

 

Use the "venturi" principle and compressed air to run it. You can pull down to about 28 inches of vacuum.

 

Bingo, there is your "venturi" principle vacuum pump!

 

Autozones in my area do not have them for rent. I check the local 4 stores and was told no at all , I have already ordered the 10 dollar job