I know lots of people who have that issue with higher end Shimano brakes (with ceramic pistons) if they let their bikes sit a while without riding. Sometimes it can be fixed by sanding the pads and rubbing them together under the tap.
I’ve heard a few explanations, all related to the ceramic pistons, but have never seen anything from Shimano on the subject.
April 29, 2020, 9:43 a.m. - Andrew Major
I know lots of people who have that issue with higher end Shimano brakes (with ceramic pistons) if they let their bikes sit a while without riding. Sometimes it can be fixed by sanding the pads and rubbing them together under the tap. I’ve heard a few explanations, all related to the ceramic pistons, but have never seen anything from Shimano on the subject.