Re: Terrible shudder under braking
I was about to say that there were recent discussions about 'warping'. The pads will want changing if they've had a good bath of oil but in all likelihood the discs will be warped or have become uneven (in terms of friction, wear, oil impregnation or whatever theory is your preferred one). If the discs aren't worn you could always have them skimmed although I haven't heard of anyone doing this for eons.
It's always a good idea to make sure the calipers are moving freely anytime you look at the brakes, they live in terrible conditions .
Doesn't say that in the manual