I clean them properly; even sand them down. Run them a couple of hours in the dry, and they are black and squeaking again.
This goes on and on.
I also properly clean the caliper and I can’t seem to find any fluid leaking. I use isopropyl alcohol.
Also inserted paper between the pistons, pushed the lever a couple times. All clean. Hose leading to the caliper is clean too.
The back of the breaking pads are also clean and free of oil.
Any ideas? It doesn’t happen to the back brake, so it must be caliper related, I think, or?
Ang ideas?
by Apprehensive_Pin9413
20 Comments
It could come from the disk.
Are you cleaning your bike with a spray foam wash that’s got a ceramic wax component?
I’ve been a shop mechanic for over 30 years. Recently I have seen so many Shimano brakes doing this.
There is no evidence of outside contamination.
Even tried different branded pads to no avail.
Squeaking doesn’t mean contaminated if the performance doesn’t change. Try a different compound, if you’re metal try resin if you’re resin try metal. Good luck.
Do they become black and squeaking while riding? Or after you’re done and put the bike away?
I’ve had a run of shimano organic pads do this recently. They seem hyper sensitive to contamination, compared to how they’ve been for the past 10 years. Super frustrating. I’ve also changed pads and discs on this one bike that is just killing me. The latest lot of changes seem to have fixed it. There was a disc on one wheel which was deeply contaminated and replacing pads and the disc at the same time fixed it. I have 5+ bikes with shimano discs
Have you properly bedded your brakes after cleaning everything?
Squeaks are common if you don’t properly bed.
Those look like the organic only rotors so maybe a chance to try something else. I’m running 2020grx 800 and have not had to touch anything and running ice tech rotors
I’ve had older XT single piston calipers leak thru the piston due to ceramic porosity so there may be a warranty issue.
Is the bleed nipple tight enough? Is the bleed nipple hole free from oil? Rat tail a paper towel and stick it up in there and see if anything is in there or if anything is sticking to the inside of the rubber nipple cap.
If it isn’t coming from bleed nipple, and you are reasonably sure it also isn’t a piston seal issue, it’s coming from somewhere not related to the bike.
So then. Could be:
Your commute takes you through an oil refinery
You buy pads on Amazon and they are counterfeit
Your front tire is bunk and leaking tubeless sealant
You ride down mountains and are getting brake fade
Once contaminated, trash both pads and rotors. 90 percent of the time it’s game over regardless of how well you “clean and sand them down”.
Pads are extremely porous and absorb oils etc extremely easily. Sanding just makes the surface look okay and, as you have experienced, quickly go back to being shit.
Rotors then get that contamination burned into them, throw new pads on and bam new pads are also fucked. I’ve had very little luck sanding, cleaning and then baking rotors to un fuck them. Works maybe 10-20 percent of the time. Maybe. Still more often than fixing contaminated pads though.
After years of dicking around with stuff and wasting countless hours I’ve realized my time and effort are better spent making a bit more money and paying for new pads and rotors if I ever truly contaminate them.
Edit: don’t replace one part at a time either, new pads and rotors at the same time. Or you just cycle back and forth continuously contaminating the new part.
Are you bedding them in properly? I’d suggest sanding/cleaning pads and rotors multiple times. Then really spend some time bedding them in.
I had slowly leaking caliper. Clean everything, then put some squares of newspaper between the pad and piston. Go for a short ride and remove the newspaper. If it shows oil you will know which piston is leaky and can try replacing the seal (major PITA). Or replace the whole caliper.
My advice is first a question; do the brakes work fine still?
If yes, whatever, send it who cares if they honk and squeak
Are they just making noise but still stopping you? Contaminated pads will sometimes squeal but not always, but they will not stop you regardless of how hard you squeeze the lever.
Exchange pads. Once contaminated,they cannot be saved most of the time. Clean rotors with alcohol and you should be fine.
Your calipers are leaking. Replace the pistons with aftermarket ones from Amazon/eBay.
my experience with a dozen shimano brakes: the non banjo type calipers tend to leak fluid easier. check if the torque is set, those need to be pretty tight.
also: these full steel rotors (RT64) were terribly loud as soon as it wasn’t dust dry. I had much better experience here with their Ice tech rotors
Tbh those don’t look contaminated to me, they look glazed which tends to happen when they’re not properly bedded in. Clean the rotors with iso (always a good idea), give the pads a good resurfacing and then properly bed them in. If you’re unsure of how to do that, check out some YouTube videos
OP I know that this might sound stupid, but have you tried running a white cloth on your brake disk and see if it comes up black? If so, it might be the disk which is oily and contaminates the pads. In which case I would advise cleaning the rotor with brake cleaner meticulously and installing new pads
Have you sanded/cleaned your discs? Sometimes using a torch on the discs can help to destroy any contaminants
Problem is, sometimes the contamination gets so deep into the pads that no amount of sanding helps and the pads are done. If this keeps happening with different sets then something fishy is going on for sure, any leak from the lever that could maybe find its way onto your disc then onto the pads? It’s a little far fetched but possible
Side note, I’m impressed that you got that retainer bolt out without wrecking it 😅