So, I have just spent two hours unsuccessfully trying to change the pads on my rear disc brakes. The problem is that the new green stuff pads are much thicker than the ones I am taking out and I am unable to get the piston to retract. I released both pins, removed the spring and took the pads out. Whatever I did I couldn't get the Pistons to retract, even when I losened the bleed valve. I detached the calipers to try and get more leverage, but to no avail. I also tried to take the calipers apart, but I was unable to take out the two outside bolts as the rear part is recessed and I was unable to get a purchase on them. I presume I am just being dumb as this must be something most of the members on this forum have done without the need to post for help, but any insight would be gratefully received.