steering violently shaking while braking..

[Hellz]

so on the highway today..

traveling about 55mph and started braking due to car in front of me.

front tires start shaking as if i was rocking the steering wheel back and forth very fast. slowly down made the shaking worse, but a little slower.

after i pulled over and looked everythign over, i drove away without any issues.
i have noticed for about the last week some minor vibrations while breaking, but nothing like this.

need some thoughts on this.

after i got home tonight, i looked it over once again.

nothign loose, or broke
i havent jacked up the front end to check lug nuts, but will be doing that.
both tires felt like they were well conencted during the shaking, not as if the tires were trying to go opposite directions, so i think the linkage is good.
steering box?
also thinking maybe brake rotors?