I need to buy a vacuum pump to evacuate my AC for a full rebuild.. I saw this and wondered if anyone had any opinions about it. It's cheap enough I might just gamble anyway... I have a good air compressor already. http://www.harborfreight.com/cpi/ct...cpc&zmam=33951326&zmas=12&zmac=112&zmap=96677 TIA
How can you go wrong for 15 bucks? It's perfect for a guy who doesn't do ac fior a living! I'd take a shot. We were checking it out last visit. Looks fine for a few uses.
I think in order to do it right you need to evacuate for 12-24 hours. Might kill your compressor. Hopefully some one will chime in here. Peace, Mike D.
I think what you're supposed to do is pull the vacuum down for :30-1:00 then close it off and see if the system holds the vacuum for 24 hours or something like that.
Don't wast your money, those won't pull enough vacuum to properly boil off moisture in an a/c system. Marginal at best for R12, worthless for R134a. I just picked up a good MasterCool deep vacuum pump off of ebay for $119 shipped, pulls down into microns. Got mine from Arctic Tools...here's another one of theirs: http://cgi.ebay.com/ebaymotors/Mast...Vacuum-Pump-Brand-New_W0QQitemZ190335153915QQ Be sure that the orings in your gauges/hoses are good - the deep vacuum needed is hard to get if they're iffy. Pull it down for 30 minutes, close the valves and turn off the pump, if it'll hold that vacuum in the system for 10-30 minutes you should be leak-free (although some leaks will only happen under pressure, not vacuum). When you're charging the system, be sure to open the can and then crack the yellow hose fitting at the gauge to get rid of any air inside the yellow hose - then charge into a vacuum, starting the engine and compressor once you get some pressure inside there. www.ackits.com has a forum with great info.
I have a HF vacuum pump. It uses alot of air and pulls a vacuum not low enough to boil off moisture.Will pull vacuum low enough to pull the freon into the system. Better than not using one at all.
Why buy one when Auto Zone or Advance Auto will lend you one for a small deposit. It won't get down to 1.0 xE-10 Torr but it does the job. Did the job for me! Thanks
I disagree, especially if you're using R134a which takes even more vacuum to boil moisture out of. A/C systems are too expensive to do half-way.
It is so simple guys. A vacuum pump, regardless of its capacity, must pull the system to about 28" ov vacuum, depending on atmospheric pressure. Using the gauges then, watch the gauge on the low side for any rise in about two hours. If none, charge the system, bearing in mind that it is pressure, not vacuum that typically causes leaks. After charging, if the system works correctly for a season, you are ok. There are few even new systems not requiring some attention once a season. With the vibration, pressures and temperature cycling encountered in any underhood environment, NO leakage is almost a pipe dream. If the vacuum pump pulls the system to at least 26" of vacuum, you are fine. It is the vacuum, not the rate or capacity that removes the moisture. Any vacuum below 10" will start vaporizing water in summertime temps. Ray
No, it's really not that simple. Pulling only 26-28" will leave enough residual air in the system to effect the system pressures. It will also not remove all of the moisture contained in the system. The recommended vacuum is 28.8" at 250-500 microns. 28.0" at 1000 microns is considered bare minimum. (In terms of vacuum, there is quite a difference between 28.0" and 28.8") Many low end mechanical pumps can barely reach that point. The venturi pumps can't even come close to that. Saying that 26" of vacuum will work good enough to evacuate an AC system is like saying sandpaper and a wood block will work good enough to hone the cylinders in an engine block.
