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Tap a-arm bores?

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  • Front Axle / Front Suspension: Tap a-arm bores?

    The guy reassembling the front end of my '59 Lark is finding the a-arm bushings so resistant to threading in the bores that he's considering tapping the bores. I don't recall any mention of that being necessary in previous accounts. I 'm not finding posts addressing that specific problem. What's the experience of you who've already been there? Thanks for your time...

  • #2
    NO, No, no! Do NOT do that!

    The fit of the ridged NOT threaded Bushings/Pin Caps into the "A" is supposed to be very tight, we used a 4 Ft. Pipe on the Breaker Bar to crank them in using the proper Spreader Tool they worked fine.
    Second Generation Stude Driver,
    Proud '54 Starliner Owner


    • #3
      There is a remote possibility of another problem here.
      A couple of years or so ago, a fresh manufacturing run was made of the upper outer pin and bushing assemblies. The overseas supplier recognized that the inner thread on the bushings was too loose, and so plated the bushings to correct the fit to the pin. This, however, made the outside of the bushing too large to the point of making it impossible to thread into the upper outer A-frame. I recall it was about .015 oversized. So, if there is evidence of bright electroplating on the bushings, it may be from said batch. A quick check would be to measure the outside diameter right where it starts in to the A-frame and compare the original to the replacement.
      I received some from my wholesaler and they were not usable, and they had by then recognized the problem and replaced them to me.


      • #4
        Here are a couple of more reasons to not tap the outer holes in the CA in addition to what StudeRich says.

        The outer bushing threads are 1 1/8" with 11 TPI. A standard ball joint tap is 1 1/8" 12 TPI.

        People have used an old bushing as a tap to pre-thread the outer holes. This should not be done either. The threads tapped into one CA ear would have to be 'clocked' to the threads in the other ear so that the distance between the crests of the threads matched the bushings and pin set used. This would be very difficult to do for several reasons. Without clocking, the difference could be as much as +/- .045". Either the bushings would cut new threads and possibly be loose or the CA ears would flex and cause the inner pin to be too tight.

        54 Commander Coupe driver
        53 Commander Hardtop project
        SE Washington State


        • #5
          Thanks, guys, for the input...probably spared us some regrettable guesswork!



          • #6
            I am not sure this is the right thread for my current problem, but I figured it might be (and I don't want to open new threads for every problem I encounter).

            On my 54 Champ K-body I am about to disassemble the front axle but I am stuck with the bushings of the lower and upper a-arms (see first pic).

            Also, the pin of the lower control arm is a miracle to me. From the body parts book I guess it should come out some way ..... but how?? (2nd pic).

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            • #7
              The pin in the lower arm is the easiest. It gets pressed out from the bottom towards the top. It is tapered. Some morons though try to put them in the wrong way when doing a rebuild and makes it a bear to remove if you don't know it. I took a 3/4" drill bushing and welded it to a piece of 1" square bar stock, set that on my press and used a 5/16" drill blank to press from the bottom side and they normally come out easy. But they are staked in at 3 spots at the top and sometimes the guy that did the staking waked it good.
              The pressed in bushings on the inner part of the arms you will have to make your own tools to push and or pull them out. I have found that the fastest way is with a slide hammer. I take an old bushing with the rubber removed and weld it to the one you want to remove with 3 or 4 good tacks and have the bushing you are using for the pulling have a piece welded to it, threaded for your hammer.


              • #8
                OK Alan, thanks for the help - sounds like some work .... just as I expected!


                • #9
                  I use an air chisel on the lower bushings. Usually just using the blade of the chisel against the lip of the bushing you can push the old bushing out. Use the A Arm as a fulcrum point if needed. Once one bushing is out the rod can be removed and the second bushing removed.
                  sigpic1966 Daytona (The First One)
                  1950 Champion Convertible
                  1950 Champion 4Dr
                  1955 President 2 Dr Hardtop
                  1957 Thunderbird


                  • #10
                    Thanks, thunderations - I managed to do it your way! Real hard work though.

                    Alan, pin came out with drilling a smaller hole into it!