I KNOW!!! I love my '03 gls but the service at the dealership sucks my a*****e dry!!!!!!

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Anyways, I think the problem with your breaks is that the rotors (or discs, however you call them) are not straight anymore so when you push on the breaks it makes it vibrate, you can feel it mostly in the steering wheel. Take your rotors of, get them machined, sand your brake pads and put them back on or in case they are not looking good change them too. To finish you can purge the system and your breaks will be like brand new, certified by yourself

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I´m sorry about the spelling, see, I'm from Mexico city.
Good luck and don't waist any more time with that answering machine.