TRW GT3 Control Arms

[steved0x]

Originally Posted by edc

Do you get the Eibach adjustable arms over there?

Those are rebranded SPC control arms, so in the US we can get them as SPC control arms. I am running them on the back. The threaded cap is supposedly pre-set at the factory for the ball joint turning torque, but since I have installed them in March, I have had to tighten them up several times, they were finger tight at one point.

I have also seen several reports of the cap totally falling off. Naturally I didn't see these until after I had bought and installed mine.

Unfortunately, there is no procedure for tightening them with the arm installed on the car, you have to remove it, and spin the ball joint with a torque wrench while tightening the cap until you get the specified torque. They suggested I use loctite, which I did.

This past weekend, both of the caps became almost fully unthreaded, which I discovered on my first warm up lap on Saturday. When I rolled into the first left hand turn of the track, the back end of the car really started wandering around, it was very scary. I reduced speed (even more, as I was on a warm up lap) and prepared to pit. When I hit the second left hander, the back end started wandering ever more. It felt just like when I did some suspension work a while back and then drove to the alignment shop when my rear toe was way off. I believe that the caps were loose, which meant there was low clamping force on the ball joint and I think it moved, reducing camber and changing my toe right in the middle of the corner.

I pitted in, jacked up the rear of the car, check the caps, both were nearly off. I tightened them (with my best guess, as remember there is no approved procedure for setting the cap except with the arm removed) and marked them with silver paint and checked them after every session, and and to tighten them again on Sunday.

I've got an idea for safety wiring the caps via the grease zerk, but if that doesn't work they are going in the trash, that will be a $700 ouch but I am going to Daytona in October and if this had happened at 150+ on the banks, I might not be here writing this. They might go in the trash anyway as I am not sure I can trust them at this point and I don't want it in the back of my mind every time I am on track...