
First suspect for vibration under breaking is that the buttons between the discs and carriers are sticking and need cleaning.
It's an easy job to do but a bit time consuming.
Put a bolt through the hole in one of the buttons and tighten a nut up on to it.
Get a can of brake cleaner and spray it on the button between the disc and the carrier - and rotate the button by turning the bolt. This should clean that button.
Repeat for every button on the disc .... and then do the same for the buttons on the other disc.
Remember to remove the bolt when you are done.
Hopefully this will sort it out for you.