955 Juddering Under Hard Braking?

Sounds like head stock bearings

 

It might be worth giving the brake disc bobbins a clean out, making sure they’re not seized up.
I’d give the calipers a good clean up too if you’re changing the pads.

 

You really need the front wheel elevated and grasping lower fork leg check for any fore and aft play. The bobbins want spinning to ensure lateral free float and to shift any fine dirt.

 

As a 'hunter and gatherer' of motorcycle mechanictry....trying learn as I go, I have heard that the bobbins being cleaned and being free to spin is good and necessary maintenance, through to not necessary...

So, just to be changed l clear - and I have more trust in this site than others - is it indeed the case that I should be looking to free up the bobbins so they spin freely?

Why is this? Is it because the disc needs to be able to float?

Isn't the disc pinched on both sides equally but the pistons - which is why the pistons need to be clean and moving freely and equally under fluid pressure?

Thank you!!

 

Yes you’re right Daniel. The bobbins need to be free to allow the slight movement between the disc and the fixed rotor they’re attached to.
This float is to allow for some axial and lateral movement to compensate for manufacturing tolerances, allowing a better pad contact therefore better braking efficiency and more even wear.

 

Freck; thank you.

I nice job to attend to when in isolation!