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caliper piston has notches for pin on back of pad?

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Yea I know another question about my disc swap. This time I noticed that on the face of the piston (part that actually touches the back of the pad) has 4 u shaped notches on four sides I also see that the back side of the disc pad that there is a small pin maybe 3-4mm wide and 2-3mm high, and it looks like it will line up with one of the notches on the piston.


Is it supposed to?/need to? Do I have to rotate the piston in its bore to line up with the pin on the back of the pad? or will it line up once you apply the brakes a few times?


I am almost ready for the maiden voyage, and I want to be sure I've got this right.


Ah the questions never seem to end. Thanks,


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Those are for turning the piston back in when you change pads. You may notice that you can't just compress them back in like you can in the front. If you could the ebrake wouldn't work. It's basically an anti-return mechanism for the pistons. Your pads should have one tab on the back which needs to fit into one of the slots after you've screwed the pistons back in.


There are special tools you can buy to turn the piston, I always just used a screwdriver, just be careful not to slip and cut the dust seal.



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I was not able to turn the piston with a screwdriver, so I made a tool that fit into two of the grooves. Worked perfect! Got a groove lined up with the pin on the back of the pad no problem.


I am searching the forums today looking for bleeding help. The back brakes bled ok, but I could not get them done out front. When pumping the brakes with the front (larger) resevoir cap off, I was seeing bubbling! and next to nothing coming out of the caliper bleeders. I'm trying to figure if my MC is faulty, or is it that I bled them wrong and now have air trapped in the MC.


I sealed and closed everything back up (bleeders and MC caps) and I hear bubbling in the large resevoir when I pump the brakes. I had working brakes before, they were not too great, but they worked.


Oh well back to searching. Found some good reading so far.



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