Anyone know anything about disc brakes?

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  • I’ve flossed the pistons and done the piston advancing procedure and still got pretty much no discernible gap between pads and rotor when I get it all back together and give it a few squeezes.

    I can see a bit of piston sticking out the calliper when the brake is released, these pads are worn but send like if the pistons would retract further then they’d work alright.

    I can see both pistons move when I pull the lever.


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    • 879CC110-7C74-4814-A9A5-3D64418F1789.jpeg
  • Leave the caliper bleed port open and then pry the pistons apart?

  • Been trying that, doesn’t seem to have much effect.

    I’ll try let a bit more out.

  • Well, between letting more fluid out and cleaning out the corners of the caliper where the pads sit it’s working a bit better still not perfect but probably as good as it’s going to get.

  • I think what you need to do is let all the fluid out, take the caliper off, put it in the bin and fit shimano.
    I have Sram brakes on 2 bikes and dread the day they need servicing

  • Just for balance I have ran these same Force hydro calipers previously, no longer have them though, but run sram red hydro and sram brakes on all 3 of my mountain bikes.

    Its possible that the pistons and seals need replaced but I've only ever replaced the pistons and seals on one Sram caliper in my years of owning them. So it might not be necessary yet.

    I've found that following the piston advancement process several times in a row is whats needed to get them back to retracting properly. I use this handy tool when servicing the code calipers. But they dont have one for the force caliper but its not really needed if you have the correct pad spacer.

    I'd advance one piston out and use a cotton bud dipped in dot fluid and really give it a good wipe. Push the piston all the way back in and then advance it again and clean it up again with a fresh cotton bud dipped in dot fluid. Do this at least 5 or 6 times - more if you can be bothered. Then repeat the process for the other piston then do a full bleed.

    I've used this process before but instead if dipping the cotton bud in dot fluid I've smeared the tiniest amount of red dot compatible grease on it and smeared it round the piston and pushed it in then advanced, repeated that a few times then advance a final time and wipe it with dot fluid, press back in then bleed.
    The dot compatible grease method isn't everyones cup of tea since if you use too much it can of course attract dirt - this is why its good to wipe it off with dot fluid on the final run.

    I think I can agree with Phil in that the servicing can be a bit more involved but if its done correctly they work very well.

    Edit - another option is using disc brake cleaner on a cotton bud instead of dot fluid then use dot fluid on the final advancement

    Another edit - if the dot fluid only method doesnt help much then try the dot grease method, I've got some I can give to you if needed, I bought a 25g tub but 25g is enough to do literally thousands of calipers...

  • not tried that but sounds good assuming the grease doesn't reduce the effectiveness of the seals as some grease can

  • it may just be the angle that the pic is taken but is your disc actually centred between the pads?

    loosen the caliper bolts, pull the brake lever so that the pads grip the disc and centre themselves, keep pulling the brake lever.

    Without letting go of the brake lever tighten the caliper bolts

  • When I took the photo I had one lazy piston and one moving more freely so I think I'd offset the caliper to account for that.

    I actually think opening the bleed port and pushing the pistons in mainly forced fluid out from the outboard side of the caliper as that is where the bleed port is. I had to open the lever bleed port and push that inboard piston back to get the fluid out from that side.

  • If I was doing that I'd just fit bb7s.

  • Can you use road sti levers and mtb calipers together? No reason other than im cheap and i have a caliper around but im really tempted to find out. Its a deore xt caliper and some non series shimano sti levers.

    the only problem is i quite like living and brakes are handy for staying alive.

  • Yeah, you can make things better by matching things that are supposed to use the same hose, but all the Shimano stuff works pretty well mixed and matched.

  • Great! will give it a shot :)

  • Wonder if that's the case with SRAM too

  • SRAM have more options for post mount road calipers, I think their piston sizes differ a bit more between the road and MTB.

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Anyone know anything about disc brakes?

Posted by Avatar for Sanddancer @Sanddancer

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