Shimmy in Steering While Braking Downhill
 

Looking for suggestions about possible causes for an issue that developed recently on my '02 Chevy Monte Carlo SS 3.8L. It has developed a shimmy / jiggle felt through the steering wheel but only when braking going downhill. Braking on flat road, no problem. Driving downhill without braking, no problem. But applying brakes while going downhill, a shimmy can be felt through the steering column.

In case it's relevant, one or more of the brake rotors needs to be turned or replaced. I feel a very slight pulsing during normal braking indicating a slightly warped rotor. But the 'shimmy' I feel while braking downhill is entirely different. It isn't felt through the brakes / brake pedal; it's felt through the steering.

Seems like it would be suspension related. Any thoughts on specifically what component could be failing? Any other ideas on where to look?

Thanks in advance for any help you can offer. :)

Time to turn or replace the front brake rotors.

The shimmy felt in the steering wheel is indicative of a warped rotor. Beyond the pulsation in the pedal, a badly warped rotor will make the steering wheel shimmy just like you described. Why does it only due it downhill? It's probably just a lot more noticeable on the downhill due to more weight being transferred onto the front tires, and the front brakes working harder.

I second the warped rotators, also when you put your wheels back on its best to use a torque wrench as over tightening the lugs can cause warpage

Thanks, guys! Guess I was trying to make it more complicated than necessary. I'll get the front rotors swapped out (and pads while I'm at it) and see what happens.