I have a recurrent problem with the brakes pulsating especially when wet. It is especially noticable when braking at low speed. At its worst, the steering wheel will shimmy rapidly above speeds of 20mph even when the brakes are not being applied. I have had the brake pads replaced and discs turned twice. The problem completely goes away after service and then returns within a few months. All three times the problem started on a very wet rainy day. I believe that the problem began after I installed after market rims. I'm wondering if the original pizza plate rims protected the brakes from water exposure. I was wondering if anyone else has had recurrent problems with warping discs. Solutions?