I have a BMW 520, year 2000 model. When I apply the brakes, there is a severe juddering noise from the offside front side. Also the ABS and the ASC warning lights come on sometimes, although not all the time, not necessarily while braking. I took it to a BMW main dealer who thought it is probably a siezed brake caliper and possibly a bad ABS sensor. They think it will be around £500 to repair. Does that sound like a reasonable diagnosis/price?
The problem first manifested itself when the car came back from some bodywork repairs. The repairs involved replacing the nearside front wing (i.e. the opposite wing to the brake that has the caliper problem) and spraying the front bumper. The bodywork repairs were carried out at a bodyshop unconnected with the BMW dealer that looked at the brakes. Could something have happened during the repair process that could have given rise to the brake problem?
impossible to answer without looking at the car im afraid,
maybe a second opinion from an independant workshop would be a good idea ?have you been back to the bodyshop with your concerns?was it an insurance job was an abs ring damaged in the accident /bump?
This certainly appears to be a misbehaving ABS system. To prove it remove the ABS supply fuse and try out the brakes again. If the fault has gone then in all probability the ABS sensor and/or the wiring back to the ABS electronic control is damaged. The diagnostics on this vehicle shpuld, however, identify the fault to the dealer's test gear.