After experiencing a vibrating sensation from the front of my '98 Sable when braking, I just replaced the rotors and pads this morning. The brake'n'shake (and we helped!) problem is now fixed.
However!!!
Before changing the discs and pads, I had been noticing that the front seemed to vibrate even when not applying the brakes. I assumed that the rotors were just so badly warped that the pads were being sideswiped every time the wheels turned. But now, after replacing the rotors, the vibration is still there?not when braking?just when coasting, maintaining speed, or accelerating. When I'm traveling in a straight line, the vibration is hardly noticeable. When I have to go around a curve in the highway, the vibration becomes very pronounced and I can hear a mild "fwapfwapfwapfwap" sound from the front.
So I jacked up the driver's side. I can't wiggle the wheel from top to bottom, but I can wiggle it from front to back. At the front edge of the tire, there's about 1/4" of slack in it. The wheel, spring, strut, and the heavy bolt at the top of the strut inside the engine compartment all move when I wiggle the wheel. Plus, there's a short bar attaching the strut to what appears to be the stabilizer bar. That short bar wiggles, too in relation to the wiggle of the wheel.
I tried the same thing on the passenger side. It's tight and there are no problems there.
What are your assumptions based on this? Ball joint? Tie rod ends? Defective cigarette lighter?
Thanks, Damaeus