I have noticed that my left calliper is giving off a lot of brake dust compared the the right and also seems to be binding on slightly as well and am wondering if after I took out all the pistons and seals earlier in the year if the seals are ever so slightly tapered although visible I cant tell and after watching a video on YT he states they have a leading and trailing edge. as always appreciate any advice
Can you push each piston back easily, or is one or more harder to do this than the others ? When you put the pistons back in, did you have any difficulty ? Usually, assuming everything was clean (i.e. no corrosion or damage) binding means you might have snagged one of the seals, so it has a slight drag. Also, daft question, but were they new pistons ? The reason i ask is because I had a mare rebuilding some calipers the beginning of the year because the new pistons had next to zero radius compared to the old ones, meaning they would not push through the new seals and did exactly what i have described above. The genuine brembo seals I bought were parallel and had no obvious face or back side that I could detect. I hope that helps.
Thanks for the reply John I didn't replace the pistons and as I didn't get an answer here I contacted someone at brakemaster service and a very helpful guy explained to me that the seals are indeed square but the recess that they sit in is not, so when I took them out there is a chance that 1 or more of the seals may have formed to the recess in the calliper and if I reinstalled them opposite to the way they came out then there is a fair chance that this could stop a piston retracting. I have since replaced with new seals and there is definitely less drag when I push the bike around but before I fitted the calliper back I did apply the brake with a piece of wood between the pads but could only see pistons on 1 side physically retract when releasing the brake lever
