I got this before on my stock rear rotors and it never went away after I applied the brakes going down a long hill high after traveling 120ish. I guess it laid brake material down and caused this. I put on a set of Stillen drilled/sloted rotors and did a similar thing tonight and it shimmied/shook again, but not after than initial brake (ie-it is fine now). Why does my car do this, NO shacking with normal braking, or driving at ANY speed. Is it because the load is just to high with BIG Tire/wheels, going down hill, braking from such a high speed????

THOUGHTS???

 

Measure the rotor [indexing] axial and radial runout per FSM............as the rotors heat up they can go out of spec...............0.0028" MAX.

 

how the hell do I measure that??

 

With a tool you dont have

 

^^^lol

 

and the knowledge I don't have either

Seriously, is this a common problem??

 

Im starting to think its a common tendency for some Z's to feel loose in the rear when braking hard. I have this issue with my JIC coilovers, though I dont remember it happening stock. Ive read of many people asking about it. In all honesty if your decent on your brakes the rotors being warped likely isnt an issue, but if you bought some cheap a$$ rotors then maybe. While warped rotors can lead to this feeling, I dont think its the issue in your case.

 

Sounds like a rear toe issue.