Audizine - An Automotive Enthusiast Community

Results 1 to 8 of 8
  1. #1
    Senior Member Three Rings
    Join Date
    Mar 05 2013
    AZ Member #
    110740
    Location
    Seattle

    Prepping A/C lines before reconnecting

    Guest-only advertisement. Register or Log In now!
    I've had my car apart for a good 5 months now and am about to begin reconnecting the A/C lines but want to make sure they're clean, dry, and anything else important before doing so. The lines still connectected in the engine bay were simply covered in paper towels and taped and have been exposed to rain and sun in that condition. Most components that came off the engine were covered in paper towels and tape as well.

    What do I need to know about prepping the A/C lines and components? I know it says to blow air opposite direction of the flow of freon but not sure which direction that is. I have most if not all the o-rings for the A/C system.

  2. #2
    Veteran Member Four Rings BCsniper's Avatar
    Join Date
    Jan 29 2010
    AZ Member #
    54160
    My Garage
    B6 S4 6MT Avant, B6 3.0 Avant 6MT (for sale), C5 A6 2.8
    Location
    north ga

    Replace the receiver/drier/accumulator whatever you want to call it then have your system flushed & vacuumed. Then replace the orifice tube and have them charge the system. Should be fine after that. Itís the vacuum thatís important here so that you get all the air and moisture out of your lines before they are charged

  3. #3
    Senior Member Three Rings
    Join Date
    Mar 05 2013
    AZ Member #
    110740
    Location
    Seattle

    Ok cool, ordering those parts now. Holding off on pressure switch unless it fails.

    So should I avoid trying to 'flush/evacuate' the lines on my own? Next steps would be just replace the drier, reconnect all the lines like normal, fill compressor with oil, take car to shop, remove orifice/restrictor, have shop evacuate lines, install new restrictor then pull vacuum and refill.

  4. #4
    Senior Member Three Rings roboto_1337's Avatar
    Join Date
    Jul 05 2016
    AZ Member #
    375740
    My Garage
    2006 S4 6MT
    Location
    Ontario, Canada

    You can replace the orifice too. Itís cheap and usually something thatís done with the drier. Hammer it with compressed air in the direction of refrigeration flow to dry it out.


    Sent from my iPhone using Audizine
    Piggy Pipes, Milltek non-res cat-back exhaust, JHM 93 Tune, JHM Short Throw Shifter, Updated RS4 upper and lower timing guides, Brembo 18Z w/RS4 SS lines, Hotchkiss RS4 Front Anti-sway bars, BC racing BR coilovers, EB-Works adjustable rear end links, 034 Motorsports spherical end links. 034 Motorsport Engine mounts, 034 Motorsports Silicon MAF hose, Hartmann 19" RS4 Reps +5mm 42DD front +10mm ECS rear.

  5. #5
    Senior Member Three Rings
    Join Date
    Mar 05 2013
    AZ Member #
    110740
    Location
    Seattle

    Yeah have a new orifice tube (Restrictor) on the way. I think I'll run a little compressed air through the lines that have been exposed to the elements and are essentially straight through lines (still on the chassis) - but in opposite direction. The manual states: Always flush or blow through components in direction opposite to refrigerant flow.

    When a shop does an evacuation before refilling are they running any refrigerant through at that time or are they only pulling a vacuum? The manual also states that some impurities can only be removed by doing a flush with R134a as opposed to just spraying with compressed air. Not sure how necessary it is to do the refrigerant flush.

  6. #6
    Established Member Two Rings
    Join Date
    Sep 16 2018
    AZ Member #
    426918
    Location
    Las Vegas, NV

    My compressor grenaded and took out the entire system. I tried flushing with a flush gun and could not get rid of the metal fines from the lines and evaporator. The flush was clean but if you held the bucket up to the sun you could see the metal fines. Ended up replacing every component except the lines. Be sure to check what washes out with your flush. I wouldn't put it back together unless it was 100% clear / clean.

    Ran a few gallons of denatured alcohol through the AC lines (off the car) and was still getting a ton of fines. Ended up spraying several gallons of water through until they were 100% clear (cuz it's cheap! - not an invitation to flame). Flushed both ways. Drained and let them sit in the Vegas sun for about 6 hours. Then blew them out with compressed air. Hooked everything up and vacuumed the system for about 3 hours then let it sit overnight under vac.

    There can be zero moisture in the system and you must vacuum it. Not optional. I did have a problem of where I had to reset the battery to get the AC compressor out of safe mode. It would not take any refrigerant until I reset it. Air is blowing a crispy 38d on full blast now . It's actually too cold at times, lol.

  7. #7
    Senior Member Three Rings
    Join Date
    Mar 05 2013
    AZ Member #
    110740
    Location
    Seattle

    Oof you went through a lot of work to clear it out! Fortunately for me there wasn't any issue with the A/C when all this engine swap/rebuild crap started so I think I'll be good as long as I clear it out well.

    What did you use to vacuum the system yourself?

    What does a shop do before refilling? Are they essentially doing a double check on removing moisture/debris as part of the 'evacuating' before 'refilling'?

  8. #8
    Established Member Two Rings
    Join Date
    Sep 16 2018
    AZ Member #
    426918
    Location
    Las Vegas, NV

    Ac was evac'd properly by a shop. I used a set of manifold gauges and a harbor freight vac pump. I would think if a shop was performing a proper flush it would be with the correct tools and inline filter to monitor debris flow. Then pulling a vacuum and making sure it holds for an hour or so. I just didnt want to take any chances. Replacing the Evap was a pain. Clean job but lengthy.

    Sent from my SM-G955U using Audizine mobile app



Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


    © 2001-2019 Audizine, Audizine.com, and Driverzines.com
    Audizine is an independently owned and operated automotive enthusiast community and news website.
    Audi and the Audi logo(s) are copyright/trademark Audi AG. Audizine is not endorsed by or affiliated with Audi AG.