brake problems

Hi folks

Since 3 days I have the following problem with the brakes:

When speed is up then 60 km/h (about 40 mph) and I brake harder, I feel vibrations on the brakepedal and the steering-wheel vibrates. Any idea what this could be? Replace the brakepads or let drag the brakedisc? I had to go so or so in garage for make the 225'000 km service.

Thanx

Kusi