a month back i had a crash where the brake lever got a clump of sand on it, so i washed it out with water and didn't have any problems, then one random day when i took my bike out for a ride i noticed the brake lever is significantly stiffer then usual, and that the pads are in hard contact with the brake rotor, i tried pushing the callipers back in, but had no affect. because before this, 70% brake lever movement was when the pads arent touching the disk, and the other 30% where your actually braking... now its 100% brake, because the pads are in constant contact with the rotor, such hard contact that it squeals when moved. (Shimano saint, if that helps)
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1By no effect when you pushed the pistons back in, does that mean you pushed on them hard and still got no movement? All of them?– Nathan KnutsonCommented Sep 27, 2021 at 16:45
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Your first task is to identify if the sand in the lever was the cause, or if the caliper has developed a separate fault. I suspect you need to disconnect the two and isolate which is failing. Do you have tools for a brake bleed, and the appropriate fluid?– Criggie ♦Commented Sep 27, 2021 at 23:38
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1 Answer
Edited - Missed that he brakes are Saint.
I have had this occur with a different brand of hydraulic disc. The lever has a valve that closes when the lever is pulled in, sealing the system so the hydraulic pressure builds and drives the pads, and opens when the lever is released, allowing the system to balance as things like heat cause fluid to expand. In my case, this valve was blocked, allowed fluid into the system but not out, jamming the brakes on. I ended up replacing them with Shimano's
A more common reason for this is the brakes have been bleed and overfilled.
I would start by attempting a brake bleed. If the fluid will not travel up thorough the lever for a bleed, disconnect the hose and you can find out if the blockage is in the lever, hose or caliper. From there, the blocked part can be serviced, or the bleed might fix it.
The crash may have bent something that is not moving freely, but otherwise its hard to explain the symptoms. A possibility is dirt, or the lever is bent, stopping the lever going into its full open position, so stopping the internal valve opening to release fluid into the reservoir.
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4I'm not sure that applies for hydraulic except in extreme circumstances...– NoiseCommented Sep 27, 2021 at 20:02
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@mattnz, i forgot to say that after the crash i went on a ride around a week later and it was completely fine, but then it was the second ride after the crash i took it out and it was like how i said. and now its got even worse, the brake pads are extremely tight on the rotor so can no longer spin the wheel. if this gives you a better idea for me to try. Commented Sep 30, 2021 at 19:19
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@mattnz i think ill try take apart both brake calliper, and then try clean out the lever and then obviously bleed the brake and see how it works, is this is a good idea? Commented Sep 30, 2021 at 19:20
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Pointing to a blocked port in the lever. Try to bleed first, it gives diagnostics to where the problem is.– mattnzCommented Sep 30, 2021 at 21:14
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I've tried bleeding it and its blocked, nothing will go through, so i have the lever separate, and have tried flushing warm water through it, but still blocked, left it in warm water for a bit, still blocked, and there are no videos for taking apart a shimano saint lever anywhere, or anything... what should i do? Commented Oct 8, 2021 at 18:19