Soft front end

You could possibly have the front end alignment checked which could cause this problem.

HiPike1450 the biggest reason for this shaking problem is the condition of your rotors - the disc your brake pad clamps down on when you apply your brakes. Most commonly, the vibration happens because the rotors have some kind of imperfection on their surface or they have changed shape (warped) over time.
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try bleeding the master cylinder at the lines first as it indicates that there is still air in the pistons
loosen one line at a time and gently apply the brakes until any air bubbles come out tighten the line before releasing the brake pedal
do it for the other line and then bleed all the brakes starting at the longest line first and ending at the shortest line

i think the felxible hose has burst ,to be honest you will have to jack it up and have a look as it could be that brake disk is worn to excess and the brake pad has come away and moved round and the piston has come out of the caliper ,either way it has to be one of these faults but you will not know till the wheel is removed

Your front brakes are at their limit most likely.

If they dont catch first the rear of the car will squat down.

You may check to see if your car has a dynamic proportioning valve for the front to rear brake bias as well.

Oh...and if it doesnt have adjustable bias....perhaps a front brake line has been pinched. which would do the same thing as raising the rear brake bias.

Does your car seem to take longer to stop? Do you have black dust all over the front wheels? Have you been bahaing over rocks or concrete parking barriers? Or even just run aground on one?

I would say start with the front brakes. Oh and make sure if you have disc brakes front and rear to use the same style pads! Better stopping power in the rear is also a brake biasing condition.

Good luck and be safe!

check that your brake cylinder is not sticking after driving feel your wheel nuts if hot that could be your problem

do u feel the vibration in the steering wheel or in the seat,i bet the most vibration was coming out of the front brakes and a little out of the rear brakes,u might want to change the rear brakes if the vibration is still annoying,also were the front wheels torqued to spec when installed?? if not u might end up with warped front brakes again,hope this helped

you have warped frt disc rotors replace them and the brake pads!

Sounds like the rotors are warped,Were they checked during brake replacement?

ASE Mechanic:
have to crawl underneath and inspected all splash guards, brakes, axles. If front end dips it is rubbing against something.