My rear Shimano disk brake is not working very efficiently, despite several bleed attempts. The front is absolutely fine, so I'm fairly confident that I am bleeding them properly. When I opened the reservoir on the back brake, I saw that the little bit of metal highlighted by the arrow in the picture below was not seated securely in the reservoir. I'm guessing this is the problem. I've tried re-seating it, but it always seems to come loose again.
Has anyone fixed a similar problem or is it new brakes time?
