Auto Parts: 2003 chevy malibu front brakes, chevy malibu, outer extremities

Question
I have a 2003 chevy malibu, I just recently bought the car and had to replace the front brake pads and rotors today, at the auto parts store I told them it was an 04 chevy malibu and he gave me the parts, I got home and noticed the pads didn't match up and thought they had made a mistake, but the rotors matched, I brought the pads back and the guy was confused and matched the pads up and gave me the correct looking pads.  After its all assembled the brake pedal is pretty soft, no air got in the lines at all, and the front driver side brake makes a funny noise when stopping.  My question is, are the 03, and 04 rotors compatible?  Should I hurry and take them off and try to switch them at the parts house??  I'm assuming he might have gave me the 03 pads the second time by matching them up, which is right.  It was totally my fault for telling them the wrong year.  Will this work or do I have to switch them??  Thanks so much

Answer
    Well, the '04 and '03 rotors are different.  I don't know what the difference is, but, given that you're having problems, I would take them back and get the right ones and not drive the car until the problem has been remedied.  It's possible that the rotor is not fitting on the bearing assembly properly.  If it's flexing, that would cause the pedal to be soft.  Also, if you have anti-lock brakes and did not purge the calipers properly when retracting the pistons, you are going to have a problem.  Unlike older cars, cars with anti-lock brakes cannot tolerate having the brake fluid forced back up into the system when retracting the pistons.  You have to put a clamp on the brake hose to prevent this from happening.  Then you must open the bleeder screw (with a hose attached to prevent air from migrating back into the caliper) and let the excess fluid be expelled from the system.  If you don't do this, the cruddy fluid  in the outer extremities of the system is forced back through the ABS pump.  The pump contains some very fine screens designed to filter the fluid, and they become clogged with the debris from the  outer system and this can cause big problems.  Repeated bleeding with fresh fluid will eventually flush the debris out, but it can use up several quarts of fluid before you get it right.