I have a very frustrating situation.

I have a recurring brake shudder. It has happened three times and I am onto my third set of discs in 10 months.

I originally replaced discs and pads with Mintex (front only) which cured the vibration completely.

3k later shudder back - came on slowly and got progressively worse.

Replaced discs only (again Mintex); shudder gone completely initially - same result after approx 6k.

Replaced discs and pads with Brembo; shudder gone completely initially- same result after 3k.

Shudder is only felt stopping at higher speeds (over 40 mph) and goes gradually from being barely noticeable to violently shuddering the pedal and steering wheel.

Each disc has clear score marks on it after driving with the shudder for approx 2k miles. Pad shaped sections can be seen on the disc.

I have not changed the brake fluid or done a bleed as the pedal is firm - could this be an issue?.

I am at wits end as to what this problem could be. I am a reasonably skilled mechanic and a mechanical engineer by profession. I have inspected the bearings, linkages, driveshafts, calipers, pistons, checked torques and followed Haynes and other online guides to the letter in replacing the parts.

I feel there could be a caliper misalignment or somehow the pads are not releasing from the disc.

Although I drive the car harder than most I refuse to believe it is just warping from stopping to hard. I am always careful to release the brakes before stopping (especially from high speed) and do not sit on the brakes while the car is stationary.

Any ideas or suggestions?