for some reason if i go really fast like 85 mph and then i start braking, the car starts shaking. Does anyone know how to fix this? do the brakes just need to be changed?

thanx

It could be any one or more of

rotors,
wheel bearings,
Tie rod ends,
ball joints.

...even Tires and alignment.

I would think...

I've got a pretty big problem with this, too. I have always assumed it'* due to cheap brake rotors that warp easily, but I'm not completely sure. Icebound was correct to suggest tires and wheels, because a tire with a broken belt or bulge can easily throw the ride out of balance. With wheels, if a wheel weight gets thrown you can feel significant vibrations, though I don't know if it would be any worse braking than accelerating.

We'll wait for a more experienced member to step in and give a little guidance . In the meantime, you might want to consider how long it has been since your pads and rotors were last changed, and whether your tires are close to the point of needing replacement.

it would make sense that it would be the tires because after i got my inner tie rods changed, i drove the car like hardcore for 3 days on the highway and ish. When i finally got my alighnment on the 4th day at sears they let me know that the tread was uneven in the front tires because I didn't get an alighnment immediately after. They told me that the tires would need to be replaced between 2-3 months. After the alignment, the car rides a lot better but the steering wheel still isn't proper for the car to go straight so I don't know if this is a result of them not doing a good job on the alignment or it'* because of me not getting the alignment sooner.

I agree with jr's3800, most probable cause would be warped rotors (excessive run-out) Take care of the tires & front end alignment also as necessary. when they do an alignment correctly, the steering wheel should be centered, if not make them aware.

are these rotors and pads easy to change... and what would cause them to be "warped"[/list]

if it were warped rotors you would be able to feel pulsing at low speed braking..

at high speeds in these cars being so heavy, its probably make the brake rotors rapidly heat and cool causing a warped feeling. thats just my 2 sense

Warping can occur when the rotor gets hot and is under some kind of uneven stress. One common source of such stress is uneven tightening of the lug nuts. Also, the contact areas between the rotor and the hub and between the rotor and the wheel should be cleaned of any corrosion or debris that might prevent a true flat mating of the rotating masses. Braking from high speeds will produce more heat and aggravate the problem.

The rotors and pads are easy to change on these cars. A couple of tips if you do change them out yourself. Make sure the sliding pins and bushings on the caliper are clean and well lubricated with silicone grease, and open the caliper bleed screw to discharge the brake fluid in the caliper when you push the piston home in its bore to make room for the new pad. This will prevent the crud that builds up in the fluid in the caliper from traveling back to and fouling the calibrated passages in your master cylinder. Top up the brake fluid reservoir when you are done.