I have trouble with my front brake squealing. I sanded the pads, cleaned the rotor with brake cleaner. Still squealing and dirty after a few brakes. I noticed small a bubbles in the caliper. Is this normal ?
Are my brake calipers leaking ?
byu/tonbretinju inbikewrench
by tonbretinju
8 Comments
No the outside should have no trace of fluid period. Only thing I can think of is if someone lubed the piston when changing pads etc and that’s what you are seeing. Probably not though.
Is the brake spongy? Looks a lot like a piston leak, or the start of one. How many miles of use? There’s normally a square gasket at the piston that gets replaced at some point. I have brakes that’s over 10 years old before I had to rebuild the caliper. The fluid most likely leaked onto your pad and contaminated it, causing the squealing. Either take it to a bike shop or consider rebuilding your caliper. If your brakes are really old, it may be cheaper cost effective to replace them. I did that to my really really old xo brakes as I can no longer get parts for them. Good luck and happy wrenching!
I would replace the piston seals.
are you just squeezing the brakes without anything (rotor, block, piece of cardboard) in there? don’t do that!!!! that’s probably why it’s leaking. without anything to stop the pistons, and probably moved past the seals
if there is no hard stop, then you cross the design limits of your brake pistons…
and if there is a leak you would know it
I would be very careful doing what you are doing. If one of them sticks then the other side will come out too far and the piston could pop right out. Try not to do this without something in between the pads.
Put a bleeding block between pistons, or piece of plastic between pads that is the same width of a disc and apply pressure on your brake lever (simulate heavy braking). Hold it like that, if you feel the lever slowly moving as you keep it squeezed you definitely have a leak. It’s not a big issue new piston seals and it’ll be as good as new.
In my experience sanding contaminated pads usually didn’t work for very long as the contamination had soaked deeper through the pads. I usually clean the rotor and brake calipers with isopropyl alcohol then put new pads in, then you need to bed the brakes again.