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I was having rubbing noises and after taking out the pads I so they were completly worn out.

I have shimano r7070 calipers so according to their specs I found in a local shop the L04C as they did not have the default L02A.

I did the following to replace them:

  1. Extract the old ones
  2. Clean with a spray designed for cleaning brakes.
  3. Push the pistons with a lever for the tyres and later with a screwdriver.
  4. Put the wheel.
  5. Release caliper, press the brake lever, and tight it to recenter.

Well, I've done that multiple times and the disc is still pinched on both sides when I put the wheel on. All components are original from shimano and less than a year old.

Any Idea on what can I do?

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2 Answers 2

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Maybe the entire system was bled with the pistons not in its full retraction. So when you push in the pistons, you're actually just applying pressure to both the master cylinder and the diaphragm of the open system structure. (and compressing the air inside, if there are any)

Try opening the bleed port and screw in the oil funnel before pushing the pistons in. While you're at it, try to squeeze out any air that could be in the system. Then carefully plug the funnel, unscrew it from the port, and close the port.

Try squeezing the brake lever a bit but not too much and see if you don't have any sticky pistons. If they're stuck, you can follow this video:

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  • Thanks, I will try this today
    – nck
    Commented Jun 16, 2019 at 11:03
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    Thank you, that was the problem. I broke a hexkey trying to open the top bolt of the lever, then with a new one some oil came out after opening it and I was able to push the pistons with the tool to measure the chain length.
    – nck
    Commented Jun 16, 2019 at 21:20
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My guess is that you are not aligning the caliper correctly.

Make sure you are pushing the pistons in all the way, install pads the the wheel, with the caliper bolts loose is there clearance between the pads and rotor before you squeeze the brake? Could you align the caliper by eye without squeezing the brakes?

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  • I'm not sure how much do I have to press the pistons, but I already put some force to put them to the sides but I,m afraid of breaking something if I try harder. Right now there is no clearance with the caliper bolts loose, the pads hit the rotor on both sides.
    – nck
    Commented Jun 15, 2019 at 16:44
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    @nck You need to push the pistons all the way in, they should be flush with the surface. Did you manage that? Take care because they are brittle, don’t damage them and push straight. They will move quite easily when you find the right spot. I would clean them first too.
    – Swifty
    Commented Jun 15, 2019 at 21:37
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    @Swifty I was only able to do it after doing what is suggested in the other response. Thanks.
    – nck
    Commented Jun 16, 2019 at 21:19

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