96 Roadmaster won't draw the R134 in

Discussion in 'The Big Chill' started by UNDERDOG350, Jul 20, 2019.

  1. UNDERDOG350

    UNDERDOG350 350 Buick purestock racer

    AC worked fine last year. Barely worked earlier this year. Doesn't work at all now.
    Background: compressor is about 4 years old. Orifice tube was replaced. Has worked fine since. Usually add a little in the spring due to leakage.

    Now the compressor was fast cycling and won't draw the freon in. I've jumped the switch and the compressor keeps running with the gauge very low, maybe 5. However its not drawing freon into the system.
    Today I pulled the orifice tube and it is clean. Reinstalled it, vacuumed and try again. About 1/2 a can will load then it won't take anymore in. The line from the orifice tube to the firewall will frost over when I jump the switch. If I don't jump the switch the compressor turns on for about 4 seconds pulls down to 30 and kicks off. Comes back on at about 50, runs for 4 seconds turns off.

    Not sure where to go with this.
    Thanks
     
  2. UNDERDOG350

    UNDERDOG350 350 Buick purestock racer

    Nothing?
     
  3. Footbag

    Footbag Well-Known Member

    Automotive A/C is something that i am still fresh in learning but i have had success with 3 vehicles over the past month so ill ask and see if i can help start this post off towards helping you find the solution. You mentioned that without jumping the compressor you see 30 psi low side and then it shuts off and climbs to around 50 psi before reengaging again. This is low side pressure correct? If so, can you report to us what the high side pressure is showing during these cycles?
     
  4. UNDERDOG350

    UNDERDOG350 350 Buick purestock racer

    Unfortunately I do not have a gauge for the high side. My manifold set is for R12. I only use cheap kits to add 134 to late model stuff. I need to find 134 gauge set and will report back.
     
  5. Electra man

    Electra man Older and Slower

    When you vacuum down are you letting it sit to check for leakage or just trying to fill it up right away? You should let it sit for at least a half hour to check for leaks. It seems like there's moisture somewhere in the system with it freezing up that quickly.
     
  6. 1973gs

    1973gs Well-Known Member

    You shouldn't have to jump the switch, especially if the system was in a vacuum. You can try setting the can on the warm intake, that sometimes helps. I've seen some of those conversion fittings fail. If the system is empty, you can replace the valve core inside the fitting. When you installed the adapter on the accumulator, did you remove the valve core from the accumulator? If you didn't, the valve core in the adapter may not be depressing the valve core in the accumulator. You should only have a valve core in the adapter, you don't need and shouldn't have one in the accumulator. Now that you jumped the switch with a paper clip, make sure that the terminals in the connector aren't spread open too much to make contact with the switch.
     
  7. UNDERDOG350

    UNDERDOG350 350 Buick purestock racer

    Holds vacuum all night. Valve core was replaced. This is an OE 134 system so there is no conversion fitting if that's what you mean.
    I've also seen these cheap refill kit quick connects fail. I tried 2 different ones with same result.
    I've got conversion connectors coming that allow use of R12 gauges. What pressures am I looking for on the high side?
    Is there something inside the accumulator that can fail?
     
  8. gsx455-4ever

    gsx455-4ever Gold Level Contributor

    Are you sure you have the right adapter ?? I have seen 2 different 134 cans . One is the type of can that you have to " Pierce " and the other has a piercing already in it so you can only put in as much as you want and save the rest . It requires a special adapter that you have to turn the can onto . Just ran into this a month ago .
     
  9. Footbag

    Footbag Well-Known Member

    Yes there are two different types of 134 cans on the market. Just like lou said. One is a pierce the top and the can is open style and then there is a self sealing can style that needs a adapter to push the flap open to allow the freon to flow out.
     
  10. Footbag

    Footbag Well-Known Member

    Pressure on the high side can vary based on the temperature of the ambient air. Some averages that i have found are attached. These are good bases to work off of and seemed to work on vehicles that i have fixed. these are the pressures while the compressor is engaged and running. IMG_2217.JPG
     
  11. UNDERDOG350

    UNDERDOG350 350 Buick purestock racer

    Ding ding ding we have a winner!
    Lou solved it first.

    Simple can tap problem. Since I have been using my cache of pierce top cans for years I didn't know they changed them. Now I had to buy new stuff it created the trouble. Damn EPA didn't consult me on this.
    I found you can still use the older style piercing can tap by just screwing it all the way down then backing it off until the freon flows. That's why it took some freon. I would screw the tap down as if piercing a can then open it all the way. When it was down it opened the valve in the can. Mine took about 1 1/2 turns from fully bottomed to allow flow. System is now blowing ice like it used to.

    Thanks to all who have responded.
    I feel like an idiot for not realizing the stuff simply was not reaching the charge port.
     
    gsx455-4ever and Footbag like this.
  12. Footbag

    Footbag Well-Known Member

    That almost happened to me too. Was wondering why nothing was going through the view glass on my gauges with a new can i purchased. Then i realized i had to back off piercing rod of the screw on can adapter. then i could see the Freon moving.
     
  13. gsx455-4ever

    gsx455-4ever Gold Level Contributor

    What do I Win ?????? Just be careful . If the system was empty you might have drawn air into the system thru that hose when you tried to put the 134 in .
     

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