Old style upper control arm problem
Posted: Tue Jun 30, 2015 8:50 pm
When we were recently at a race, a friend of ours mentioned that he had an old style upper control arm fail, where the pin makes the connection to the bar. I had never heard of this. If you look downward at an upper control arm, you will see two inside bushings that are welded in place to eliminate any play from the upper adjustable rod end going down to the bar.
When I was checking to make sure there was no preload on our car, I found that one of the inner bushings was very lose and that this bushing was just spot welded in two places. I then checked the other front upper control arm by using a pen light where the pin goes in. You could see that there was a gap between the welded bushing and the control arm. The bushing was not lose, but because it was just spot welded in two spots, you could see the light.
My guess is that the bushing, on our friends car first broke lose, thus putting extra pressure on the part it was welded to. As a result, it failed. Not good!
Our chassis is # 855 so it's not that old and you might want to check your old style
upper control arms. I am taking them all in and have them welded all around the bushings, rather than just spot welded. This should be a safe fix, thus avoiding a much larger problem.
Pat
When I was checking to make sure there was no preload on our car, I found that one of the inner bushings was very lose and that this bushing was just spot welded in two places. I then checked the other front upper control arm by using a pen light where the pin goes in. You could see that there was a gap between the welded bushing and the control arm. The bushing was not lose, but because it was just spot welded in two spots, you could see the light.
My guess is that the bushing, on our friends car first broke lose, thus putting extra pressure on the part it was welded to. As a result, it failed. Not good!
Our chassis is # 855 so it's not that old and you might want to check your old style
upper control arms. I am taking them all in and have them welded all around the bushings, rather than just spot welded. This should be a safe fix, thus avoiding a much larger problem.
Pat