Has anyone ever had hydraulic brakes just fix themselves?
So I had some slight audible rubbing on the front brake for awhile. Couldn't get the caliper centered in a way that would let it clear. I ended up replacing the disc, put new pads on and then thought it was fixed but it was soon after rubbing at higher speeds. Around the same time I had what I thought(maybe it was?) air in the line as it started to feel kinda squishy(which is why I replaced the pads in the first place, hoping it was just worn pads). The strange thing is after riding it pretty regularly(about 50-70k/day for a week) everything just works now. Lever is firm and there is no rub. I'm slightly inexperienced with working with hydraulics but is this a thing that happens? I saw something about shimano breaks working air out of the system naturally but these are tektro.
Posted Sep 12, 2021, 3:04 PM UTC
Pretty much all hydraulic brakes have some sort of fluid reservoir to accommodate extra volume of fluid. If bubbles rise into the reservoir they are effectively out of the hydraulic line and do not compress anymore. Intentionally making bubbles rise without changing the fluid is known as "burping" and sometimes does the trick instead of a full bleed.
Rubbing can be due to many things, like a misaligned caliper. A recurring problem can be caused by sticky pistons. The solution involves cleaning, lubricating, and working the pistons to free them. It could be that regular use helped free your pistons.
Yeah the sticky Pistons was my best guess with the rubbing as well. I didn't end up working on them because on another one of my bikes I had really sticky/stuck ones and managed to snap the piston trying to put it back. I guess I'll do the whole clean up thing more carefully when the problem eventually reasserts itself.
FYI, you don't need to take the pistons out entirely to clean them.
Also, that is what I would do to if it is working for now: clean things next time you need a bleed or change of pads.
I know the drill. It's like dab mineral oil and work them in and out. The one I had was literally seized but like these arent ceramic so I won't have the same issue. It's just one of those bike fixing trauma deals that I haven't worked through I guess
Haha, yeah. Thankfully I have no had something like this happen but I can imagine the reluctance to try again!