Did you just ShartQ?

Nothing too crazy, ring-wise, don’t think there’s any leak. The pads do look pretty glazy, though. I did discover that one of the iso bolts was completely missing and the caliper was able to rotate pretty freely in the vertical plane. Which, is concerning…

How the heck did that bolt fall out?

Your guess is as good as mine, I was just doing some stuff with the brakes last week, can’t imagine I wouldn’t have seen/noticed given how loose the caliper was. Popped this silver guy in and tightened the other up

Are they honking like hell? If not, probably not oil. Sand the pads. Wash the rotors really well with hot soapy water then sand the rotor a bit too and try to burn things back in.

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He said they are howling and he’s in like the driest place around. I bet they’re leaking. I had constant fouling issues until I replaced those calipers with XTR. When in doubt, replace with XTR.

Oop… yep. Proper fucked.

The lack of oil on the back of the pads leads me to believe it might just be a sloppy bleed.

I’d still give it a shot with cleaning, but Shimano rotors love to hold onto contamination in my experience. Rotor and pads are likely destined for the bin.

I’d more than believe I did a sloppy bleed job. Gave everything a clean and sand, will see what that does

Edit: honking is mostly gone except under full braking, but rear has almost 0 power. Gonna try to rebleed, then may have to replace the pad/rotor

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Rebled the rear with extra care, didn’t improve the situation. I have spare pads. Is it worth replacing them and not also doing the rotor? If I don’t replace the rotor, should give that a very thorough clean and sanding, yeah?

Or, is this time to replace the RS785 caliper with something like an XT, per @Crustradamus suggestion

I have never been able to revive contaminated pads and rotors despite doing all of things including sanding, burning, and scrubbing with alcohol, degreaser and soap. I legit put my pads on the other side of the room when I do my bleeds.

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Same and I also don’t think sanding rotors does anything beside make them look ugly. Tho I feel like a good alcohol rub could decontaminate them?

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my pet theory here is that oil gets on the rotor arms and as soon as the wheel spins it wicks back out onto the nice complex surface you’ve just sanded onto the braking surface.

I kinda want to make a little alcohol bath to see if that helps, the next time I get a rotor all oiled up

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I just haven’t had to deal with any of that since I threw those shimano calipers in the trash years ago

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I’ve had pads that couldn’t be salvaged, but usually rotors can. Unless they’re rainbow colored, then time for new ones

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I use a pie tin and it doesn’t seem to matter.

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I’ve had great luck holding the pads in a vise or pliers and blasting with a propane torch until they stop smoking


I’ve also used that method with reasonably good results.

I’ve used that method and it didn’t do anything because my calipers were leaking.


My RS505 calipers would leak. I had read about people replacing the o-ring.

I bought the wrong size, because the 505 has a larger port. Instead, I just cleaned the faces of each side of the caliper and torqued it to 5 Nm.

That was a few years back and I haven’t had any leaks since.

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highly recommend a full caliper tear down, if only for learning how simple the thing is.

Until they stop smoking? This should, in theory, burn off any contamination?