Having an issue with my brakes.
Brake was staying on/dragging. Not locked on, but enough to give notable drag. Wheel wouldnt spin freely.
Thought maybe it was sticky pistons, so did the popping them out individually and lubing. On putting the pads back in though, I've found the issue is that the pads are coming together (pistons coming out of the caliper, pads going inwards, its hard to phrase this right) of their own accord.
Pads are about half worn. Bike lives wheel off in the shed at home, but issue began on day 3 of a trip where the wheel had not been removed for the duration.
Any ideas?
Air in the system. Its been compressed when the brakes are used and expanding when you leave the bike. Its the only thing I can think of
also are you centering them the hope way? Not the squeeze and tighten method
What did you use to lube the pistons? What have you used in the past? Maybe its contaminated the seals and caused them to swell.
Lubed with the recommended fluid (forgotten what its called but I did splurge on the proper stuff for this)
However, I have cleaned the brake dust and muck off with IPA? could this have messed with the seals?
Yep - centred the proper way. Squeeze and tighten only really works on 2 piston brakes.
If it wasnt clear on the OP, the pads moving of their own accord happens in a period of about 5-10 seconds after I have pushed the pistons back in. Occured in the workshop back garden as well as when riding, so not a heat issue - although giving them a bleed cant hurt I guess.
I cannot think of anything but air in the system -possibly trapped behind the piston
Make sure the reservoir is open when you push the pistons back in. If it's full of air, it'll push them back out again.
Make sure the reservoir is open when you push the pistons back in. If it’s full of air, it’ll push them back out again.
will that be enough to push the air bubbles out if it's down at the piston/caliper end?
Too much oil in system. Did you have pistons fully retracted and pop a bleed block in to keep them that way when bleeding . I find its very easy done .
too much fluid would mean the pistons cannot be pushed back in. fluid is non compressable. it can only be air being compressed then expanding.
A bleed has sorted a similar issue for me in the past when I had E4's. Air behind piston, work each piston out one at a time, open nipple and push piston back.
I have a few set of E4s and had a similar problem, brakes were sticking on tried bleeding and cleaning pistons.
Bunged in a set of new pads and problem went away, could be thenpads are too worn and need replacing.
Similar to austy, half worn pads would bind on. I replaced the rotor as it was down to about 1.1mm on the calipers and that sorted the problem.
