Anyone know anything about disc brakes?

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  • So Ive brought a set of what we’re meant to be fully bled SRAM Rival breaks & callipers. Didn’t want to have to deal with the Dot5.1 fluid as I’ve heard it’s pretty nasty stuff.

    First thing I notice, the hoses are slightly too long on the front and a fair bit too long on the rear (this is an XL frame-set...?) not a deal breaker.

    After installing, I hand it to my friend to try out the breaks to find that Dot5.1 fluid is leaking from under the hoods. You can imagine my face.

    I’m wondering if anyone else has had this kind of issue with sram hydro systems? Or have I just got unlucky?

  • All SRAM brakes are obviously horrible, but they shouldn't just be leaking, they new? Being too long is normal, because being too short is much more difficult to fix.

  • Yep, they are brand-new. I’ve only ever set up Shimano so was pretty ignorant about SRAM. Back to the manufacturer they go.

  • Where are they leaking from? Is something just not done up tight? Not that I want to convince you to stick with SRAM, but generally they work new, at least without leaking everywhere.

  • It seemed to be leaking out of the bleed port, it wasn’t finger loose. But unfortunately don’t have a small enough torx Allen to be able to investigate further. What is noticeable is there is a spongy liquid / air noise when squeezing the rear break - sounded like it was drawing in air on the decompression. I had this kind of issue when I lost the olive from the bleed port screw with my Shimano set up. This was posted as a complete bled unit, surely the olive can’t be missing??

  • You'd hope not, especially as I think they use weird ones. I'd say get the seller to cover the cost of an LBS repair, but most shops are booked up for ages. Just send them back and get shimano.

  • Any advice on removing stuck pistons? I can't seem to push them back in or force them further out.

  • What brakes? What have you tried so far? Are they stuck in or out?

  • Shimano RS505. Pistons stuck in.

    Have tried bleeding the system, forcing them out with mineral oil, have soaked them in degreaser to try and free them up. I've got one piston moving but the other won't budge

    Edit: Now got it moving

  • My advice is to take it to a reputable LBS and ask them to see it they can do anything, as this sound like a delicate issues that can easily damage the piston if further attempt is being made.

    Worse come to worse is a new caliper which isn’t expensive.

  • I seem to have got it working. I'll ride it for a bit and see, if it holds up then all good. If not, then yes new caliper time.

  • Hopefully need a good bedding in to free up the piston!

  • Shimano RS505. Pistons stuck in.

    Have tried bleeding the system, forcing them out with mineral oil, have soaked them in degreaser to try and free them up. I've got one piston moving but the other won't budge.

    The usual advice for this is to hold in the moving piston (with a tyre lever, spanner, or similar), then pump the lever, so all the hydraulic pressure should then go to the stuck piston.

    Last time this happened on an ancient set of Shimano brakes I had to both apply a bit of gentle pressure from a syringe at the lever to get it to come out. This is a a bit of a last resort as you can damage seals applying too much pressure.

    Then once they're out clean them up with some brake cleaner, and apply a few drops of mineral oil.

  • The usual advice for this is to hold in the moving piston (with a tyre lever, spanner, or similar), then pump the lever, so all the hydraulic pressure should then go to the stuck piston.

    This is what worked in the end

  • Just taken it for a ride around the block and the front brake now leaks fluid so looks like I need a new one.

  • There's a small venting hole over the bladder, a bad installation or just an overfilled brake and they'll be leaking some oil there.
    But if they're new brakes don't bother fiddling, send them back.

  • Thanks again for the advice in my moment of need. Parts & Labour came thought and saved me with same-day turn around.

  • Any reason why running Sram Paceline rotors with Shimano Dura Ace calipers wouldn't be a good idea? I much prefer the look (and price) of the Paceline rotors so would like to give them a whirl. I assume they'll work fine?

  • I’ve been running SRAM rotors with Shimano callipers of years, haven’t died yet.

  • Cool I figured they'd be fine but then again compatibility issues are de rigueur in cycling.

  • Yeah I’ve been running SRAM rotors with Shimano callipers no problem

  • Why does my front disk brake make a kind of tapping sound when actuated? It doesn't seem to do it when I'm stationary.

  • It's trying to get your attention?

  • Pads are gone and/or the spring is touching the rotor

  • Did you says this before or after inspecting the pads and rotors?

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Anyone know anything about disc brakes?

Posted by Avatar for Sanddancer @Sanddancer

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