Why my 91 Accord EX shakes when braking at 55 - 70 MPH? At low speed, it brakes smoothly. I just got 4 wheels balancing 1 weeks ago and changed my rotor 2 weeks ago.

 

your brake discs are warped.

 

could be only your pads are out. Also could be discs.

 

I just replace brand new OEM discs and pads 2 weeks ago. Discs can't be warped. Pads can't go bad that fast.

 

i would just take it back to a shop or take it all apart to make sure everything is in working order

 

braking system, need wheel alignment, worn tires, suspension parts. you will more than likely find your culprit within on or more of the listed.

 

Worn caliper spring clips can cause that problem. Did they replace the spring clips or reuse the old ones?

 

I changed my own brake rotor and pads. I reused the old spring. I will go back and check it.

 

check your balljoints or have the shop do it

 

Have you checked the rotors for runout and parallelism?

 

When you replaced the pads, were they evenly worn or was one worn much more than the rest?

It is possible that something is sticking, either a piston in the caliper or some other moving part of the caliper assembly (sorry, I don't remember just which caliper assembly your car has).

New does not necessarily mean "good". It is possible that the new rotors have a problem so check them for runout to be sure.

There was a suggestion to check ball joints. While doing that do not forget to check the tie rod ends as they can be a source of trouble also.

Good Luck

 

If the shake was also at low speed I would say replace the rotors.
Torque your wheels or remove the wheels and check for ANY debris between teh wheel and rotor. Reinstall the wheels and torque your wheels.