My car has 65,000 miles and the steering wheel has started to shake when braking (when driving fast than 40 MPH). I ordered a set of new front grooved/slotted brakes. I do a lot of highway driving, and therefore a lot of braking. The problem stayed after replacing the front brakes. The dealership suggested that the rear rotors were rotted. So, I ordered new rear brakes and rotors. But the problem still didn't go away. One thing I noticed is that the shaking only happens when you lightly tap the brakes, not when slamming the brakes. I made an appointment to see the dealer again, but would like to have some ideas as to what this might be. Any advice?
Since you have already replaced the front and rear rotors, I suspect the problem is in the steering or suspension. The first thing that comes to mind is a worn wheel bearing/hub assembly, but other parts of the steering/suspension could be the cause as well. I have also seen brand new rotors warp due to hard braking and excessive heat. So, it’s possible the new set of rotors you installed has already become warped.
Since the dealer couldn’t fix your problem the first time, I suggest having it looked at by a certified mechanic to fix your shaking problem. They will be able come to your location to diagnose your vehicle firsthand.