Removing fittings from L84 intake manifold - NCRS Discussion Boards

Removing fittings from L84 intake manifold

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  • Michael G.
    Extremely Frequent Poster
    • November 11, 2008
    • 2155

    Removing fittings from L84 intake manifold

    I'm trying to remove a heater hose fitting from my aluminum intake manifold. I've tried a breaker bar, an impact wrench, and I've heated the manifold. No luck. Before I start sawing this thing, I read in the archeives that heating the fitting and then applying wax to the threads works. Sounds easy, but are we talking just enough heat to melt the wax, or, something else? Does anybody know how much heat to apply and with what kind of torch?

    Thanks, Mike
  • Larry M.
    Extremely Frequent Poster
    • December 31, 1991
    • 2688

    #2
    Re: Removing fittings from L84 intake manifold

    Mike:

    I think what makes this trick work, is you heat the fitting hot enough so that when you remove the heat, capillary action draws the wax into the threads as they cool......essentially the same as lead soldering a copper pipe. Based on this, you should be able to accomplish with a propane/MAP plumbing torch. Especially if the manifold is off the engine/car, where you have more room to work with the wider flame tip.

    I would stay away from the aluminum itself, and try to heat the fitting to around 400-500F. If you have an IR gun you could shoot the fitting and surrounding area to get a temperature, otherwise heat for about 30-60 seconds and try it. The wax will smoke a bit when doing this. Use small birthday candles.

    Aluminum melts at around 1200 F. Don't go that high.

    Larry

    Comment

    • Joe C.
      Expired
      • August 31, 1999
      • 4598

      #3
      Re: Removing fittings from L84 intake manifold

      Originally posted by Larry Mulder (20401)
      Mike:

      I think what makes this trick work, is you heat the fitting hot enough so that when you remove the heat, capillary action draws the wax into the threads as they cool......essentially the same as lead soldering a copper pipe. Based on this, you should be able to accomplish with a propane/MAP plumbing torch. Especially if the manifold is off the engine/car, where you have more room to work with the wider flame tip.

      I would stay away from the aluminum itself, and try to heat the fitting to around 400-500F. If you have an IR gun you could shoot the fitting and surrounding area to get a temperature, otherwise heat for about 30-60 seconds and try it. The wax will smoke a bit when doing this. Use small birthday candles.

      Aluminum melts at around 1200 F. Don't go that high.

      Larry
      MAPP gas with O2.
      Propane alone not hot enough.
      STAY AWAY from the aluminum.....as was said, only heat the fitting, but heat it DULL red hot

      Comment

      • Larry M.
        Extremely Frequent Poster
        • December 31, 1991
        • 2688

        #4
        Re: Removing fittings from L84 intake manifold

        Dull red hot for steel is approximately 800 - 1000 F. This may be too high for something threaded into aluminum, which melts at around 1200 F. I would be okay with this temperature if it were steel on steel, but not steel on aluminum.

        I still recommend the lower temperature to start. You can always increase it.

        Larry

        Comment

        • John D.
          Extremely Frequent Poster
          • November 30, 1979
          • 5507

          #5
          Re: Removing fittings from L84 intake manifold

          Be very careful as it doesn't take much to destroy the aluminum threads. As mentioned in a post like this a few days ago penetrating oil helps also. Use the shock treatment too. Bubba method. Take a hammer and smack the front of the fitting a couple of good wacks. I see Joe does it the opposite of us. Joe says to heat the fitting. We heat the aluminum. Whatever gets the job done. Meanwhile I should not have said we as I hurt my back enough over the years on the damn fittings. I farm it out. JD

          Comment

          • Michael G.
            Extremely Frequent Poster
            • November 11, 2008
            • 2155

            #6
            Re: Removing fittings from L84 intake manifold

            John, I already tried heating the aluminum and smacking the fitting.

            I have a question, though: is the passenger side fitting (with the hex) supposed to get painted orange? I ask because the fitting's actually in good shape, so if I paint it orange you can't see the degraded zinc plating. Maybe I won't have to take it out.

            Thanks

            Comment

            • Terry F.
              Expired
              • September 30, 1992
              • 2061

              #7
              Re: Removing fittings from L84 intake manifold

              Truly, I would leave the fitting alone. I have messed with aluminum housings on boat engines. Trying to remove something steel that has been threaded into aluminum (for a good number of years) is practically impossible. If you get lucky enough to loosen it, it will take a good portion of the thread with it. It will more than likely not have the same integrity. Wire brush it and find some good silver paint. I like the silver paint used for exhaust pipes. Has very little build and is tough. JMHO, Terry

              Comment

              • Michael G.
                Extremely Frequent Poster
                • November 11, 2008
                • 2155

                #8
                Re: Removing fittings from L84 intake manifold

                I think you're probably correct Terry. Since the manifold is already on the engine, I'm hesitant to do much more than I've already done without removing it. Given the small surface of fitting exposed after the hose is installed, painting with a metallic silver will most likely be indistinguishable from a new fitting. I'll try this first, I can always take more drastic action after I've seen the result of the painting.

                Thanks, Mike

                Comment

                • John D.
                  Extremely Frequent Poster
                  • November 30, 1979
                  • 5507

                  #9
                  Re: Removing fittings from L84 intake manifold

                  Originally posted by Michael Garver (49693)
                  John, I already tried heating the aluminum and smacking the fitting.

                  I have a question, though: is the passenger side fitting (with the hex) supposed to get painted orange? I ask because the fitting's actually in good shape, so if I paint it orange you can't see the degraded zinc plating. Maybe I won't have to take it out.

                  Thanks
                  Although I can't get away with painting fittings on a restoration since it is your car and all anyone will see is the hex part of the fitting when the hose is on it might not be a bad idea to cheat on it. Sounds like the only way the fitting is going to come out is to burn it out. EDM??
                  I don't think that fitting had any orange paint on it. Now the other fitting-the bypass fittings do for sure. John

                  Comment

                  • Michael G.
                    Extremely Frequent Poster
                    • November 11, 2008
                    • 2155

                    #10
                    Re: Removing fittings from L84 intake manifold

                    John, the fitting is not badly corroded, its just not "new" looking, it has some "grey" spots, from plating oxidation, not red base-metal rust. I think the proper paint will stop the corrosion and make it look pretty again. Its worth a try; if it doesn't look right, I can always EDM the fitting out. I'd have to take off the base plate again to do this, so its a last resort.

                    Thanks, Mike

                    Comment

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