Burning smell, juddering and swerving when braking

What is your question?

After the engine/car is warm ( 45 mins or so) and speed over 60 mph there is a burning smell - then a vibration which becomes a thumping noise. If you brake hard the car swerves. After slowing down it all stops, but if you speed up again it starts again. Not tyres, not brakes, not bearings. Garage cannot solve.