Shuddering when braking

[kalpol]

I've had a weird shudder when braking rather hard in my 79 280SE. If I brake fairly hard from 60-70, I get a pretty big shudder in the steering from one of the front wheels. I had an out-of-round tire develop that was causing a really bad shudder on braking and acceleration, and when I replaced the tires a few weeks ago it was all much better until this morning I braked rather hard (while changing lanes, so more load on the left front wheel) and there it was again, just not as bad and only on braking. If I had to guess, I'd say warped rotor, but I replaced both front rotors about 10-15k miles ago when I did the front brakes.....

....so if it is a warped rotor, what causes fairly new rotors to warp? What else might it be? Ball joints? The suspension is in decent condition - newish Bilsteins and when I had the tires put on i had them take a look at bushings and they said everything looked all right.

any help is appreciated, thanks!

[ggenovez]

Warped rotors are usualy caused by overheating. Either cheap steel or you live in a mountenous area and need to use your brakes a lot.

You should be able to check that by putting a straight edge accross the face of the rotor on several places. Any gap indicates a warped rotor.

[meltedpanda]

i have also read, not experienced, that rotors can be warped by improper applcation of bolt torque. Using the old air hammer technique with ft pd's above 90 can do it.
When i get my tires done, i request hand torque of lug nuts only.
Heat, as mentioned is the other culprit