The only way the SPC ball joint can rotate is if the pressed in plate rotates and that's unlikely. Have you looked at your upper A-arm mounts? When they start to pull away from the frame your alignment will change. Take a dental pick and push it through the sealer and probe between the upper rear A-arm mount and frame.

On another note my alignment was slipping at the front left camber adjuster. I had to really crank it down (highere than specified torque) to keep it from slipping. If you haven't already you should scribe witness marks at all your alignment adjusters so you'll know if they slip.

 

My A-Arms are custom seam welded.

As I loosen the top nut to rotate the top plate, the whole ball joint swivels....

Does that mean the press-in plate is moving? I can't see it because things are still bolted together.

 

A couple of things to clarify:

1. Do you mean the you have the mounting locations where the upper A-arm bolts is seam welded?

2. When you say loosen the top nut to rotate the plate, what do you mean? You should not be 'rotating' the plate but rather, if you're using the slots to adjust camber, you are sliding the threaded stud along the slot in the upper plates.

3. When you say the whole ball joint swivels, do you mean the OFFSET swivels? So that you could, in effect, just by swiveling it you could effectively do the same thing as if you installed it in the opposite direction? Is it spinning within the hole in the A-arm where it is supposed to be pressed-in, or is it doing this internally (under the silicone boot, perhaps take that off and see what is going on).

If you mean just that the ball joint moves around and/or spins in place, well that's what it is supposed to do.

I'm not trying to be a smart-ass, I just do not understand what you are saying is happening.

 

Hahaha. No problem. I didn't think you were being a smarty pants.

1. The brackets of the upper A-Arms on my AP1 are seam welded (like an AP2).

2. I loosened the flat top nut and was able to rotate the top plate perpendicularly to "lock" the threaded stud from sliding.

3. When tightening the top nut again, the whole ball joint housing rotates. You know how people can rotate the built-in offset to give more or less static camber? Well, the whole thing is rotating. To the point where I needed a large wrench to hold the ball joint housing just underneath the arm, but above the rubber boot. I think this is normal and I'd imagine that the whole unit would be able to rotate (using the threaded stud as an axis point)... this is all separate from the designed intent of the ball part of the joint.

So basically the whole unit can rotate under enough stress, I think. Even if it's clamped down tightly, you have a little torque arm (the little offset inherent to the ball joint housing) that can be pushed and affects camber and toe if it rotates even a little.

 

So, like the previous picture in the thread:



If I tighten the top nut, my top plate doesn't move and the stud is "locked in place." But you can see the part underneath rotating and the offset built into the joint changes. So for illustration (I know that the pictures are two different sides) the part underneath goes from looking like picture 1 to picture 2.

Obviously, if I clamp the top nut down it won't rotate as easily, but my point (I think) is that if there is an offset bushing and the wheel pushes against the rack due to extreme offsets, it may straighten the joint by rotating it (a separate thing from the plate sliding).

 

It sounds like your bottom plate is spinning in the upper A-arm. The ball joints should not rotate when applying the 120 lb-ft of torque to the top nut.

 

I agree with robrob, it sounds and looks like it is spinning within the A-arm. I don't see this as being a problem with the SPC joint, unless yours is defective (i.e. below tolerance for the press fit).

Unlike what you describe, after properly pressing the slide plate into the A-arm, I was easily able to fully torque the nut without the joint spinning within the A-arm, though I cannot guarantee that all would have that same experience due to variability of parts.

CKit, you didn't use some sort of grease to help press the slide plate into the control arm, did you?

 

I think you guys are right. The bottom plate must be spinning in the A-Arm. It used to be pressed in and previously, I could tighten the top nut without holding the bottom. But somehow, the plate can now spin under stress. Last year, when the joints were fresh, it would take extreme measures like off-course spins to even minorly tweak the alignment. This progressively got worse to now needing alignments after almost every event. I don't think it's due to factory adjuster failure, although his may be an issue.

If the joint is spinning in the arm, then it's time for new arms anyway. I got a good deal on a set of used upper and lower arms and ordered a set of J's racing S1 roll center joints. It's probably just as well, I could use wider lower arms rather than narrower upper as we're into the shock bodies as it is.

 

Cool, I hope it works out for you CKit.

And if you were at all quick while the car was dynamically aligning itself on you, it might be a whole world nicer afterward.

Good Luck!

 

Thanks! Check it out. This was what we had to drive at a local event... the "even" slaloms were quite interesting....


I almost bought full alignment equipment, but realized that this is probably a better solution. Simplify!