James_Douglas Posted February 25, 2021 Report Share Posted February 25, 2021 I managed to get out of town a couple of weeks back and drive the 1949 Desoto for a second long drive since turning the Caster adjusters all the way to rear on the eccentric shaft. Car is 95% better in terms of the problems I have bee having. (see old threads if interested). Like I said in the previous thread, I managed to get the Castor a little closer to zero from negative two. Of course the manual warns you not to run that Caster nut all the way to one end or the other as binding against the control arm will result. One of the things I am planning on doing is to drop the lower control arms and "turn" the shaft to the rear thus moving the control arm to the front of the car. That will move the bottom of the spindle upright to the front of the car thus increasing Caster. The question is, how many turns? I have an upper control arm here in San Francisco and I set it up to measure how much it moves for each turn. I am assuming the thread pitch is the same for the upper and lower. What I got surprised me. We all know that those threads are course inside the mounting bushing and the threaded ends of the shaft itself. But, I ended up measuring that for each turn you get approximately 3/32 of an inch of movement. I got 0.090 to 0.105 depending on where and how I measured it. I do not have a caliper large enough to measure end to end. I was thinking that 2 or 3 turns were going to be necessary to bring the caster nut back to the middle of the upright while maintaining my current Caster setting. But right now I am thinking of one turn or two at the most. What this does show is that the tool for setting the control arms is a must. Or making one with the exact same dimensions. On my lowers, I had made a temporary tool during the restoration, but obviously it was not good enough. I have the tool for the upper control arms. If one is out even one turn it can toss the range of adjustment too far off to get a proper Caster adjustment and keep the Caster nut near the middle of the eccentric shaft. James. 1 Quote Link to comment Share on other sites More sharing options...
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