Originally Posted by
cxwrench
Wrong and wrong. As the OP now knows that is for the FS headset adjustment. The yellow block is obviously too thick to fit between pads...it's a bleed block. It only fits w/ the pads removed and pistons pushed back all the way.
I did think the yellow block seemed a bit thick to "replace" the disc when the wheel was removed. So I should find something to maintain the space (I recall blowing it on my mt bike years ago on my first and only flat) for a ride side flat repair. Road bikes are more prone.