Fastfred- The trick to keep the threads from blowing out is to thread the tie rod all the way in on the arm side of the upper arm, then back it out a turn or two ( this will allow some room for camber adjustment). Then unscrew the ball cup as far as neccessary to re-align the camber. Your camder rod will now be off center twards the middle of the car. this allows more rod to reside in the plastic, and will no longer crack or pull out of the plastic arm. Once I started doing this, I've never blown out an upper arm.-Jeff