Something is rattling up under the bottom of the car. everytime i hit a bump in the road something is rattling

Usual problem is tailpipe/muffler. Clamp attaching to body failed, so muffler will hit the body making noise. worse is rusted out muffler/tailpipe.

Could be the suspension strut and/or upper mount is bad.

check sway links, ball joints, tie rods and strut bushings, they can all make noise. i would guess sway links

A loose pad could do it.
Check the pad anti-rattle clips again. The pads should be snug in the calipers. Its possible the new pads are not the exact same shape as the old ones.

take the door panel off and have a look ,must be something loose but without looking who knows

It could be a heatsheild on the manifold, muffler or catalytic converter. Or on the underbody above the exhaust system.

i would check stabilizer bushings and/or links

Check your exhaust and rear suspension for something loose or broken. Problem could be the exhaust, a hanger or cracked pipe. In the suspension it could be shocks, worn bushings, track arms etc. When a problem like this happens you have to get under the car and grab and try to move things checking for loosness. In general try to see what is loose enough that a bump causes it to rattle or bang. Other than inspecting the rear area there is no short cut that can be taken to solve the problem. You don't want to just start replacing parts hoping to fix the problem, that can be expxnsive and unnecessary. Good Luck!!!

Sounds like a broken U clamp. Get under the car and pull on the exhaust (while its cold) and see where the tailpipe has broken free from the bottom of the car. Then secure it with a new clamp. In a pinch, have always used a wire hanger for emergency repair.

It's probably the rear sway bar links. If you can jack your car up and check right behind both rear wheels you will be abale to see the sway bar which is connected to short links about 5in long with ball joints.

If either of them are broken or not connected anymore it can cause some pretty loud noises when you ride on rough roads or hit bumps. They run about $35 per link so it's not a very expensive repair.