You got new brakes and roters but sometimes you hit brakes and you here a grinding sound and it seems like the brakes lock for a minute before they let go and stop1995 Grand Marquis?

If the problem persists go back and have the mecahnic check them again, sounds like faulty brake pads, the locking sounds a bit dangerous - may want to take it straight in to get re-checked

if the mechanic says there good then the mechabic working on them might have got grese on them wich is causing the lock up. as for the grinding goes then if you baught brake pads that are supposed to last for over 30,000 miles then they are no good because good brake pads are only supposed to last around 30,000 miles. so it isn't always good to buy the best brake pads.