i changed my brakes 4 wheels 2 weeks ago
right away they were shaking in the front

not when im on the pedal light or hard it does it in between
shakes the steering wheel and brake pedal

 

Did you clean the new rotors before installation? They almost always have some sort of coating on them to prevent rusting during storage and shipment. It will mess up the pads if it is left on.

 

yes..

 

You need to be bedding your pads when you change them. Proper bedding improves pedal feel, reduces or eliminates brake squeal, prevents (and often cures) brake judder, reduces brake dust, and extends the life of your pads and rotors.

StopTech : Balanced Brake Upgrades

From 60mph, gently apply the brakes a couple of times to bring them up to operating temperature. This prevents you from thermally shocking the rotors and pads in the next steps.

Make eight to ten near-stops from 60mph to about 10-15 mph. Do it HARD by pressing the brakes firmly, but do not lock the wheels or engage ABS. At the end of each slowdown, immediately accelerate back to 60mph and then apply the brakes again. DO NOT COME TO A COMPLETE STOP! If you stop completely and sit with your foot on the brake pedal, you will imprint pad material onto the hot rotors, which could lead to vibration and uneven braking.

The brakes may begin to fade after the 7th or 8th near-stop. This fade will stabilize, but not completely go away until the brakes have fully cooled. A strong smell from the brakes, and even some smoke, is normal.

After the last near-stop, accelerate back up to speed and cruise for a while, using the brakes as little as possible. The brakes need only a few minutes to cool down. Try not to become trapped in traffic or come to a complete stop while the brakes are still very hot.

After the break-in cycle, there should be a slight blue tint and a light gray film on the rotor face. The blue tint tells you the rotor has reached break-in temperature and the gray film is pad material starting to transfer onto the rotor face. This is what you are looking for. The best braking occurs when there is an even layer of of pad material deposited across the rotors. This minimizes squealing, increases braking torque, and maximizes pad and rotor life.

 

Before you start that procedure:

Step 0: Start the engine and pump the brake pedal until it feels normal.
Step 0a: Accelerate to about 10 mph and try the brakes to make sure they're going to work at all.

Then you don't seem like an idiot when you get to step 1 where you're going 60 mph with unproven brakes.

I've found that 2 or 3 hard near-stops from 30 mph are sufficient. You should notice the brake performance improve substantially (up to normal levels) by the third one. Continuing until you're making smoke seems like a bad idea.

 

were the old rotors really bad? they might have left some rust on the mating surface. Else maybe just a defective new rotor? That happened to me with a brake drum once, auto store probably dropped it or something

Can you feel the shaking from one side or both sides of the car?

 

sanded it

 

Maybe try the 30mph stops, if that doesn't work, then try the normal procedure I guess. Anything is better than not breaking in at all.