de-pressurizing ac system [Archive] - Forum


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06-25-2011, 10:56 PM
anyone ever done it themselves? i'm getting ready to replace the entire system myself, and i'm almost certain there's no 134 left in it b/c of a leak.

if i pushed in the port where you fill it with r134, would i be able to tell if it was still pressurized or not?

06-25-2011, 11:01 PM
i would just move the car outside and disconnect the lines...just don't let anybody see you do it haha

06-26-2011, 05:15 AM
If you open the lines to the atmosphere (disconnect them) then you should get them evacuated before you try and fill up with 134a again. You could have condensation buildup inside the lines that will shorten the life of a compressor. When mine leaked I just took it to a shop and had them evac the lines and refill it with refrigerant and a UV dye in case it ever leaks again.

Also remember that it cant draw any 134a in if there is air in the lines already since the refrigerant cant displace the air (which is why the lines have to be evacuated).

06-26-2011, 08:38 AM
^Listen to that guy.

If you don't have the lines vacuumed down before they're charged, you'll also shorten the life of your receiver/drier by loading it with extra moisture in the system that it has to absorb.

Why are you replacing the entire system though?

06-28-2011, 04:01 PM
metal shavings throughout the system--at least that's what the shop told me---that i'd have to replace the compressor, condensor, lines, ect.

06-28-2011, 04:37 PM
how do you know there are metal shavings in the system? are they just guessing? what failed? to check if there is pressure in the system just get a screwdriver and press on the low pressure port and see if it hisses. That still does not mean you have enough refrigerant in the system. check to see if your compressor clutch is engaging before doing anything. if not check the compressor to see if it is locked up. try spinning the center of the pulley which is the clutch system. it should spin not real easy, but shouldn't take too much effort. if you are trying to do all this yourself you can get manifold gauges at harbor frieght to really check the pressures. and to refill the system after the repairs. you might still be able to rent a vacum pump from autozone and vacuum the system down yourself.

i just did a VW AC system last week. the compressor took a **** and i picked up a new unit and replaced the dryer and the expansion valve. we dont have an AC setup here at the shop so i just took it to a local shop here where we have "friends". I had them vacuum down the system and then fill it and test for leaks. its less work for me and i know its done right because they have all the proper equipment. i can buy the stuff todo it, but with as few AC jobs that i take on i really dont want to spend the money for tools that will likely sit on the shelf more then they would get used.

06-29-2011, 05:18 PM
I don't think the metal shavings would get past the the orifice - have the system recovered - and then take it out and just wash out the lines with some distilled water (or reg water) - it will only be 1 line to clean/replace and the pump - you won't need a new dryer or condenser.

06-29-2011, 08:45 PM
I don't think the metal shavings would get past the the orifice - have the system recovered - and then take it out and just wash out the lines with some distilled water (or reg water) - it will only be 1 line to clean/replace and the pump - you won't need a new dryer or condenser.

It is unwise to skip replacement of the receiver/dryer. In many (if not virtually all) instances, a parts retailer will refuse to honor a warranty on a compressor if the customer cannot prove the R/D was replaced concurrently.

AC components should be flushed with the proper solvent. Water will not effectively remove refrigerant oil, and debris will accumulate in refrigerant oil residues.

Lots of debris will accumulate in the condenser after a compressor failure, although frequently it will tend to settle in the bottom and doesn't always get carried out to the liquid line after repairs are made. Flush the suction/discharge hose assembly and the liquid line, and flush the condenser as well as possible.

06-29-2011, 08:53 PM
Plastic knows more then I - as I have never cleaned a line - ;) replace it all cost ya a 500$ in parts..

07-19-2011, 02:41 PM
just got back from meineke,
need new condenser and receiver/dryer.

quoted me at $585.93

but i'll end up getting the parts online and doing it myself.

the one thing that i argued with him about was an orifice tube. he tried telling me that our gagt's don't have one! he said every GM model after 1996 only has an expansion tube connected to the compressor.........

oh well, i'll get an orifice tube anyway.

i went to and am looking at condensers, spectra makes one for $70. anyone have any experience with these condensers or website?

07-19-2011, 02:52 PM
Get the Tube our cars have one :)

07-19-2011, 08:04 PM
The thing with A/C repair is that it takes special equipment to do it right, which is why shops charge what they do. If you want to do it yourself to save some money and know what you are doing, take it to a shop and have them evacuate the system. Then buy the parts and install them and take it back to the shop to have them recharge the system. That way the shop will use the proper amount of PAG oil, refrigerant and they may even add dye in the event that there are future leaks.

I had my wife's Pontiac Vibe in the shop today for a recharge. I had the system evacuated previously and then installed a used compressor that I found on car-part. The receiver/drier was $30 at Napa, which I had the shop install at the time of recharge. The expensive part for me was the installation as the receiver/drier unit called for 2.9 hours which I did not realize it took that much time to replace, but I confirmed that I was not overcharged on Alldata. The shop owner commented it was rough getting it out as it is behind the grill and what not on the Vibe. Over all I have roughly $430 in getting the A/C working again, but when it is 95 degrees out, I see it as money well spent knowing that it is done right. The shop did add dye in the event that there is a leak in the future.

07-20-2011, 05:20 PM
just got back from meineke,

Theres your first problem.

Find a smaller reputable shop.