Air Conditioner problems of the 1998 Chevrolet Lumina

I purchased my vehicle used and it still had 1000 mile warranty from the dealer. When I got the car there was a problem with the fuel pump so they replaced it. Before I even got out of the parking lot the (vibration shudder hose) went bad. Or at least that is what the guy at the service area told me the name was. They have replaced that. And for almost two years now I have been fighting with them that the power steering has been whining. Also the brakes do not stop to well in the rain. I travel a lot and we go through brakes like water. We also had the ac compressor go out last year during the summer. The car was only 4 years old. We keep our car up very well. I do not understand all these problems. I know this may not seem like big problems but when I keep my car up and have been fighting with the dealer due to whining this is frustrating.