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Technical technical A/C

Discussion in 'Traditional Hot Rods' started by studebaker46, Nov 23, 2019.

  1. studebaker46
    Joined: Nov 14, 2007
    Posts: 682

    studebaker46
    Member

    I am putting a/c in my 41 ford p/u. the vintage air evaporator housing was cracked so I am using an under dash much like the old mark 1V unit the problem I am having is I can't pull a vacuum or get it to accept Freon. sanden compressor gm drier and binary switch by passed. I know a/c is not traditional,but I am and being 71 I like my creature comforts,any thoughts or suggestions greatly appreciated Tom
     
  2. If you can’t pull a vacuum then you have a leak


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  3. Ziggster
    Joined: Aug 27, 2018
    Posts: 913

    Ziggster
    Member

    You need to be able to pull a vacuum down to about 29-30 inches of Hg. Once you shut off the vacuum pump and gages, it should hold the same vacuum reading. If not, you have a leak, and first need to fix it before adding any refrigerant.
     
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  4. If you can't pull and hold vacuum you probably have a leak somewhere. HRP
     

  5. rockable
    Joined: Dec 21, 2009
    Posts: 3,429

    rockable
    ALLIANCE MEMBER

    Two different things. Are you trying to pull a vacuum with a vacuum pump or can you just not get the compressor to kick in and start drawing in Freon?

    Pulling a vacuum on the system to insure you've removed all moisture and have a leak free system should be done before charging.

    After that, you must put enough pressurized Freon into the system to "make" the binary switch and pull in the clutch to the compressor. A full can will usually do that but you can jumper the two wire of the binary switch together to get the compressor clutch to pull in, if needed.
     
  6. I understand you wanting creature comforts, last year I finally added heat to my sedan after going 31 years without it, I used vintage heat/air and I can attest with some of the trips we took this summer, running air we were very comfortable.

    I haven't used the heat much but it will run you outta the car when cranked uo on high. HRP

    Make sure you didn't forget a " O " ring & check to make sure the connections are tight.
     
  7. grimmfalcon138
    Joined: Jan 14, 2010
    Posts: 164

    grimmfalcon138
    Member
    from az

    Pump the system full of nitrogen. Check all of your connections and all brazed joints with soapy water in a spray bottle. If you have a leak that will find it.
     
  8. David Gersic
    Joined: Feb 15, 2015
    Posts: 2,400

    David Gersic
    Member
    from DeKalb, IL

    If you can’t pull a vacuum on it, assuming you’re actually using a vacuum pump (you didn’t say...), you have a leak. Don’t waste your refrigerant. Charge the system with nitrogen, get some soapy water and go leak hunting. Check every joint, then check the evaporator and condenser.

    If you’re using new parts, they should be good. If they’re “remanufactured”, sometimes that just means that they hit it with a rattle can and shipped it.

    I’d be concerned that your vintage air parts are damaged. If they’re new, contact vintage air and get replacements. If they’re used, whoever pulled them off whatever they were on may not have been careful not to damage anything else.



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  9. 325w
    Joined: Feb 18, 2008
    Posts: 5,609

    325w
    ALLIANCE MEMBER

    Most times my mistake is mocking it all up. Then forgetting to install an O ring someplace.
     
  10. fordflambe
    Joined: Apr 9, 2007
    Posts: 554

    fordflambe
    Member

    Lube up the o'rings too! The oil helps o'ring slip in place and seat properly. It is easy to roll, nick, or cut an o'ring and cause a leak............I've damaged one before and had problems pulling a vacuum.
     
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  11. Blues4U
    Joined: Oct 1, 2015
    Posts: 5,701

    Blues4U
    Member
    from So Cal

    I think he means he can't get the system to draw in freon, not that he can't draw a vacuum in the system. He's jumped the low pressure switch and still can't get the compressor to kick on, if I'm reading his post correctly.
     
  12. DIYGUY
    Joined: Sep 8, 2015
    Posts: 883

    DIYGUY
    Member
    from West, TX

    I had that problem awhile back and I think it was my can adapter as far as charging. Pulled a vacuum ok.
    Might be your equipment, not your vehicle.
     
  13. David Gersic
    Joined: Feb 15, 2015
    Posts: 2,400

    David Gersic
    Member
    from DeKalb, IL

    Yeah, it’s not clear. IMHO, if he’s not vacuuming it down first, it’s wrong anyway. Stop there.



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  14. sunbeam
    Joined: Oct 22, 2010
    Posts: 5,277

    sunbeam
    Member

    DIYGUY and rockable like this.
  15. studebaker46
    Joined: Nov 14, 2007
    Posts: 682

    studebaker46
    Member

    the compressor is kicking on but cant get it to pull vacuum or accept Freon. I replaced the evaporator and the hoses from the drier to evap and evap to the fire wall. will pull apart and check orings. will report back with findings thanks for the help thus far Tom
     
  16. Joe H
    Joined: Feb 10, 2008
    Posts: 1,080

    Joe H
    Member

    That makes no sense, if the compressor is kicking on ( on its own ) then you have some freon in the system. If you are manually kicking the compressor on, then you have a valve problem either at the gauge connection or on the A/C line. Are you using the 134A to R12 system adaptors? If so, pull the guts out of the R12 valves before screwing on the 134A adaptors. O-rings will not keep it from accepting Freon, they let it leak out!
    Sounds like a valve problem.
     
  17. saltflats
    Joined: Aug 14, 2007
    Posts: 10,843

    saltflats
    Member
    from Missouri

    As sunbeam said, if you have the self sealing 134A can you have to use a self sealing can tap.
     
  18. sunbeam
    Joined: Oct 22, 2010
    Posts: 5,277

    sunbeam
    Member

    What kind of vacuum pump if it is an electric not one of those air powered ones check the outlet on the vacuum pump. Air coming out after its run awhile you have a leak no air when first hooked up I'd look for a schrader valve in the adapter for 134.
     
  19. DIYGUY
    Joined: Sep 8, 2015
    Posts: 883

    DIYGUY
    Member
    from West, TX

    Well crap I didn’t know there was a new style can. That explains a lot. I do have two cans that are different from each other.
    Thanks Sunbeam!
     
    Last edited: Nov 24, 2019

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