A/C Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**special-K** · 06-03-2005, 06:42 AM

What is the best way to handle an A/C system that has been open?From what I understand,the moisture that has entered will make ice balls and clog itup.Does any one have a trick to get moisture out of a system that has been left open?

Terry Peerson · 06-03-2005, 07:23 AM

You will have to pull a vacuum on your system after it is put back together. I always pull a vacuum to 30"Hg (that's 30-inches of Mercury) for at least 2-hours (although technically, 30"Hg is physically impossible). This will cause the water in the system to "flash" to a vapor and will be removed by the vacuum pump. After 2-hours (longer if you're not in a hurry), shut down the pump and leave the gauges on for at least 1/2-hour to make sure the system holds a steady vacuum. If it doesn't, you have a leak in the system that will have to be repaired before charging. After the leak is fixed, you will have to do the whole vacuum thing again prior to charging. Most people do not have the equipment to do this (vacuum pump and gauges). But, usually, you can find a friend that does. So you don't have to pay the ridiculous prices that a A/C-shop will charge you.

It's not too tough. You CAN do this!

Good Luck!

T

smokekiki · 06-03-2005, 09:15 AM

I just went to Napa yesterday.They have a vacuum pump and gauges for $200.00.Comes with a free thermometer.That is for a mastercool pump.$10 more for an advanced tool pump.I am thinking about doing my own work.It costs that much to have the system checked.Go to www.ackits.com Lots of info on a/c work.There is alink to a forum at the top of the site.

sneakysnake · 06-03-2005, 02:15 PM

If there is any chance of debris or forien matter flush with 134 or blow clean with nitrogen

**john** · 06-03-2005, 04:52 PM

Dont forget to replace the drier before pulling vacuum. It will be contaminated with moisture etc. John

06-03-2005, 06:42 AM	#1
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,858	A/C Question What is the best way to handle an A/C system that has been open?From what I understand,the moisture that has entered will make ice balls and clog itup.Does any one have a trick to get moisture out of a system that has been left open? __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

06-03-2005, 09:15 AM	#3
smokekiki Mike Join Date: Jan 2003 Location: west chester pa Posts: 2,474	I just went to Napa yesterday.They have a vacuum pump and gauges for $200.00.Comes with a free thermometer.That is for a mastercool pump.$10 more for an advanced tool pump.I am thinking about doing my own work.It costs that much to have the system checked.Go to www.ackits.com Lots of info on a/c work.There is alink to a forum at the top of the site. __________________ 70'c/10, 71 suburban4x4 402bb, 72suburban 4/6 drop, 72k/5 4x4 blazer 4" lift 35 tires

06-03-2005, 04:52 PM	#5
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Dont forget to replace the drier before pulling vacuum. It will be contaminated with moisture etc. John __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/

06-03-2005, 07:23 AM	#2
Terry Peerson Registered User Join Date: Aug 2003 Location: Bonner Springs, KS Posts: 311	You will have to pull a vacuum on your system after it is put back together. I always pull a vacuum to 30"Hg (that's 30-inches of Mercury) for at least 2-hours (although technically, 30"Hg is physically impossible). This will cause the water in the system to "flash" to a vapor and will be removed by the vacuum pump. After 2-hours (longer if you're not in a hurry), shut down the pump and leave the gauges on for at least 1/2-hour to make sure the system holds a steady vacuum. If it doesn't, you have a leak in the system that will have to be repaired before charging. After the leak is fixed, you will have to do the whole vacuum thing again prior to charging. Most people do not have the equipment to do this (vacuum pump and gauges). But, usually, you can find a friend that does. So you don't have to pay the ridiculous prices that a A/C-shop will charge you. It's not too tough. You CAN do this! Good Luck! T

06-03-2005, 02:15 PM	#4
sneakysnake It's a catastrophic success. Join Date: Jan 2003 Location: Oklahoma Posts: 2,077	If there is any chance of debris or forien matter flush with 134 or blow clean with nitrogen



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