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Thread: Compressor

  1. #1
    Junior Member
    Join Date:  Dec 2015

    Location:  Lawrenceville, GA

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    My VIN:    SCEDT26T5BD001815

    Compressor

    Need to replace compressor (and probably entire system as all is original). Who has the best setup for R134a?

    Thanks...

  2. #2
    Delorean Guru
    Join Date:  May 2011

    Location:  Northern NJ

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    My VIN:    10757

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    My advice is to stick with R-12. Replace the three hoses, dryer/accumulator, and compressor. If the insides are still clean don't touch the orifice tube. You may also need a new belt and idler bearings. Since your compressor failed you should flush the evap and cond coils to remove any possible bits.
    David Teitelbaum

  3. #3
    Senior Member
    Join Date:  Feb 2016

    Posts:    943

    My advice is to convert to R134. Unless they are damaged, leave original components in place. Flush the system thoroughly with mineral spirits and compressed air, ideally blowing from the low side backwards to the high side. Pour out mineral oil in the compressor and replace it with Ester oil. Use steel R134 port adapters with integrated schrader valves from NAPA (remove the original schrader valves) rather than aluminum push pin adapters from most parts houses/Wally World/etc. Pull a vacuum before recharging. Adjust low side pressure switch to ~25 PSI.

    Then enjoy ice cold air from the vents.

    Bill Robertson
    #5939

  4. #4
    Senior Member
    Join Date:  Jun 2016

    Posts:    214

    Quote Originally Posted by content22207_2 View Post
    My advice is to convert to R134. Unless they are damaged, leave original components in place. Flush the system thoroughly with mineral spirits and compressed air, ideally blowing from the low side backwards to the high side. Pour out mineral oil in the compressor and replace it with Ester oil. Use steel R134 port adapters with integrated schrader valves from NAPA (remove the original schrader valves) rather than aluminum push pin adapters from most parts houses/Wally World/etc. Pull a vacuum before recharging. Adjust low side pressure switch to ~25 PSI.

    Then enjoy ice cold air from the vents.

    Bill Robertson
    #5939
    I'm looking at redoing the A/C in my car. I just bought the harbor freight A/C manifold set and I'm borrowing a vacuum pump from work. Why do we need to replace the schrader valves? Are the stock ones aluminum too?

    Also, you hooked your air compressor up to the low side and blow backward through to the high side? I was thinking about hooking my air compressor up and pumping the system up to 10-20psi to look for leaks, is that a bad idea? I've not done any A/C work before so I don't know what is a "bad idea" yet. :P

  5. #5
    Senior Member
    Join Date:  Feb 2016

    Posts:    943

    Be advised: this afternoon I took my Harbor Freight manifold set apart and cleaned out all the glue they use to seal the NPT fittings. A piece must have broken loose and stopped up the low side because the gauge wasn't reading properly and it wouldn't pull freon from a canister (it's been acting up with the bus, and when I tried to use it this afternoon on the DeLorean it wouldn't read at all). I reassembled it with teflon tape and everything's working properly now.

    The converson fittings sold at Wally World and chain parts houses don't have schrader valves -- they have a pin that
    presses on the original R12 schrader valve. A piece of bent metal serves as the spring. Hold one up to the light and look though it. If that pin ever goes off center it will bend, and can even jamb the original schrader valve open.

    NAPA sells conversion fittings that have their own schrader valves. You remove the original schrader valves and screw the NAPA fittings onto the wide open R12 ports. NAPA's conversion fittings are also made of steel. Wally World/chain parts house conversion fittings are quite flimsy aluminum (you have to be careful installing them not to strip the threads out).

    I like to flush backwards because you're pushing away from the orifice tube restriction, not into it. Obviously you need an air compressor and a blow nozzle to do that. In their absence you can use the A/C compressor itself to push the flushing fluid through, but you'll need to do it forwards (high side to low) because that's the only way the hoses will bolt up to the compressor (leave the low side hose loose obviously so the flushing fluid can get pushed through.

    You can even use the engine itself to pull the vacuum. A vacuum pump is optimal, but in a pinch the engine will work. Just attach a charging hose to a manifold vacuum nipple (you'll need an R134 to hose barb adapter -- I believe the 134 threads are 1/2 ACME). That's how we did a quick and dirty R134 conversion on Rich Roger's car at DCS'14 so he'd have A/C for the drive back to New York. He actually lived quite well on that conversion all summer until we redid it properly with an air compressor and vacuum pump at a tech session in Pennsylvania that fall.

    Bill Robertson
    #5939
    Last edited by content22207_2; 07-28-2016 at 05:21 PM.

  6. #6
    Senior Member Henrik's Avatar
    Join Date:  Sep 2011

    Location:  Frisco, TX

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    Club(s):   (SCDC) (DCUK)

    If/when you decide to convert to R134, my advice is to follow the manufacturer's procedure: http://www.sanden.com/objects/retro.pdf.

    Sanden's support page has a lot of good info too: http://www.sanden.com/support.html

  7. #7
    Senior Member
    Join Date:  Feb 2016

    Posts:    943

    Some fun tools I carry in my cubby for A/C work (on the road or at home):

    R134 to vacuum hose adapter:

    R134VacuumAdapter1.jpg

    Obviously this is for engine vacuuming (for example in a DCS parking lot). Adapter with R134 and 1/4" vacuum hoses attached:

    R134VacuumAdapter2.jpg

    This hose allows me to attach an air compressor to pump up the system and look for leaks (spray suspected leaks with soapy water -- just like looking for a tire leak):

    R134AirCompressorAdapter.jpg

    Bill Robertson
    #5939

  8. #8
    Senior Member
    Join Date:  Feb 2016

    Posts:    943

    Before everybody's brains explode: I assure you -- I have proper A/C tools (including 30 lbs canisters of freon). I just don't carry them in the car at all times.

    ACTools.jpg

    I carry small scale substitutes that work well enough in a pinch (can I hear an "Amen" Rich?). Faced with a choice between a good enough to get home conversion and driving a thousand miles with no A/C, which would you choose?

    Bill Robertson
    #5939

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