I bought my 2003 Carrera 4s in November, and at that time the car stopped smoothly. Recently, I am feeling vibration in the steering wheel on braking. The pads have plenty of material left. Any advise before I head off to the dealer to have the rotors turned?

 

It's probably the rotors, dealer will probably try to talk you into replacing them

 

Rotors do not and cannot warp. Most likely, the vibration is being caused by the transfer of some pad material to the rotor, creating a high spot. Some aggressive, long braking will remove the material.

 

I agree that OEM rotors will not warp (if within spec and not already turned), but the same cannot be said of aftermarket rotors. I would also suggest replacing the pads at the same time. I stay with OEM pads and rotors all the time for my C4S. This whole process is an easy DIY, and can save you hundreds of dollars. Check the DIY on Rennlist and the threads for the procedures. Should only take a couple of hours from start to finish with simple tools.

 

Good advice. Thanks. I will be replacing front pads and rotors soon!

 

try cutting the rotors..before replacing them

 

If I can find a place to cut the rotors should I replace the pads too? I have plenty left.

 

I have yet to come across a rotor that if true to begin with is not easily trued again by a few long, hard brake runs. As I said before, your brakes cannot get hot enough to warp the discs. The imperfection is pad material and nothing else. Using a pad of the same material to sand the disc, is all you need to get rid of the pad material causing the vibration.

This assumes the hub and wheel flange are flat and in good condition and that the wheel bolts are evenly torqued.

There have been numerous studies on this issue including by the DOT which have confirmed this. The only time it is necessary to replace a disc is when they wear down to minimum specs.

This is also true with clutch flywheels, although turning them down or grinding them is a simpler way to remve disc material.