i just did my front brakes on my buick.....rotors pads everything....there the ceramic pads...since my uncle was showing me how to do brakes and such, well i dunno what is happening when i press on the brakes like at around 50+ the front end shakes as if the rotors are warped but there brand new....so you got any ideas on why its doing that? and whats usually the lifespan on the timing chain the 3.3L if you all know? i just baught it like 15,000 miles ago and it has 124,000 on it now...just wondering if i should think about replacing it soon or what? and what are warning signs with the timing chain? or one of those things on day it works and the next day is snaps and bends valves?