Car shakes when I brake, usually down hill or accelerated speed.

 

Where do you want to start?
First off, what model, year and mileage are you driving.
Secondly, do a search in the forum for shaking under braking, this will show threads of previous braking issues and one of those may show your symptoms and resolution.
Thirdly, if you cannot find the resolution to your problem doing a search of the forum, then people here will pipe in and assist as necessary.

However, my first bet would be pads and rotors dependant on your mileage.

 

Ting, I'll give you a free pass since this is your first post. Normally, the usual response goes something like what "trosty" wrote in his reply. Just don't let it happen again!


I don't claim to be an expert on cars but I suspect you have warped brake rotors.


Good luck.