endless problems...

I just got a 1995 GT. Love the car but loaded with problems. I didnt realize it but it had been in a wreck before I got it and Im not sure what all was messed up that wasnt fixed. Today coming down the interstate I went to slow down and when I put on the brakes the car pulled really hard to the right and almost changed lanes for me. What could it be?
 
Do you have any experience doing brakes? You can pull them off the rotors and have someone pump the brakes while you look at that rotor, it could be jammed up with something, rare, but ive seen it happen years ago on one of my cars
 
If it pulled hard to the right, either your left caliper is shot, or, ive seen this happen to my stepson right after he put pads in his truck, put the pads in wrong on one side and they fell out somewhere rending that side useless so pulled to the other side that was working fine. Thats very dangerous as Vibrant mentioned. Check them out asap, you should more than likely be able to see whats going on.
 
I do have some experience with brakes but I just moved so I have no garage or mechanics that I trust to not screw me over. I'm planning on replacing all of that asap. As for the rattles, the front end rattles almost sounds like something or everything is loose or maybe all the bushings shot? Also the rear of the car squeaks while going down the road and def a stiff ride. I just got back from getting exhaust work done and on the passenger side in the rear a bolt from the backside of the rotor going in looked loose and come to find out it was cross threaded
 
When i first got my car i was told by the owner that the rear brakes needed to be done because of a grinding issue. What i found was the pad back plate with no brake material left and the other pad was nowhere to be seen leaving the caliper piston directly making contact with the rotor.
 
When I got mine there was an annoying ding that would keep beeping then go away but sometimes randomly come back and come to find out it was a warning light that they had busted the bulb to so you couldnt tell what it was and after I realized it was a salvage title and had been wrecked I tried contacted him to find out what all was messed up he wouldnt ever respond.