Vibration in the front end beginning about 30 mph and when braking - what is causing?
Bad tire or tire balance.
Worn ball joint,
Worn inner tie rods.
Worn outer tie rod ends.
Worn CV joints.
Loose wheel bearings.
This is one of those problems that will require a hands-on approach to narrow it down.
Don’t forget to inspect the upper and lower control arm bushings.