Our 2007 GS430 has been back to the dealers (Lexus Perth, Australia) about 8 times to try to get the bottom of a weird issue. Forgive me posting here but this forum has a much higher membership that the Australian one.
Basically, when braking from circa 60mph (or sometimes below) there is a low frequency / high oscillation rumble that comes through the brake pedal. It is intermittent, but seems to occur more often after higher speeds.
The dealer witnessed the problem but could find nothing wrong after checking the brakes and suspension. In the end they replaced the from disks under warranty although not the pads. The problem remained, so after another 3-400 miles they also replaced the pads and skimmed the front disks. The problems still remains, so now the car is going in to have the rear disks skimmed tomorrow.
Any ideas as to what might be causing this? I'm getting fed up with this trial and error.
Thanks,
Marcus.