# Cleaning calipers and decontaminating pads



## juan pablo (Jan 17, 2007)

Any tips on cleaning brake calipers and decontaminating pads?
My Shimano brakes are flawless in terms of just plain working and it has resulted in zero maintenance other than the rare bleed. I want to clean all the pad residue and other crap off the caliper and clean the pistons. What is the best method and cleaning agent? If I remember correctly, once the caliper is clean you can extend the piston and put a dab of brake fluid on before pushing them back, is this correct?

I also seem to have an arsenal of contaminated pads, mostly from a couple of years ago when I seemed to have a bad habit of spoiling the pads. I have read 2 methods, bake in the oven or using Acetone. Any improved methods? I figure I may as well give it a go and use them on my trail bike.


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## SHIVER ME TIMBERS (Jan 12, 2004)

best bet on *cleaning pads* is just throw them away...you will never get 100% grabbing power with a contaminated pad. You can try burning them in fire and all kinds of cleanes but just throw the pads away

*cleaning rotors*.....wipe down with alcohol and scratch them lightly with sand paper

*cleaning calipers and pistons* with rotor and no brake pads...pulse one piston outward and clean all the dirt with a small tooth brush. If it is real dirty then pull out piston wipe down (be careful around O-ring.and re install...repeat other side.after reinstalling both pistons. Clean whole caliper with rubbing alcohol. (if brakes are older then 3 years it is a good idea to replace O-ring but not necessary)

then bleed your brake lines

have fun


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## uncle-mofo (Jul 14, 2006)

You may aswell try salvage the pads with a mixture of solvent and fire. Nothing to lose, except your eyebrows.


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## SHIVER ME TIMBERS (Jan 12, 2004)

uncle-mofo said:


> You may aswell try salvage the pads with a mixture of solvent and fire. Nothing to lose, except your eyebrows.


never works as good...pads are cheap....just replace them


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## XSL_WiLL (Nov 2, 2004)

With Shimano brakes, make sure you don't use DOT fluid to lube your pistons. Use Shimano mineral oil or silicone grease/spray.


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## mtg7aa (Jul 11, 2008)

Yeah, if you accidentally contaminated the pads with oil or brake fluid, just save your time and get new pads- as said above, they're never the same.

Since you said they still work fine, that sounds like they aren't contaminated with oil, maybe just dirty or glazed or something. In that case, lightly sand them with sand paper.

Re: your question about dabbing brake fluid on the piston when sliding it back in. Brake fluid is generally used to lubricate the inner parts of calipers and master cylinders when re-assembling. However, if any of it gets on the brake pad, refer to above (ie throw pads away). So, lubing a caliper piston with brake fluid does help to reassemble, but make sure you clean off all of the excess (isopropyl or brake parts cleaner) before getting your brake pads anywhere near the caliper.

And, +1 for SMT, that's good advice.


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## FullMonty (Nov 3, 2008)

This because it doesn't smell nearly as bad as pretty much anything else I've used. I also give a quick spritz with water since the brake cleaner tends to leave a bit of a residue.


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## Freerydejunky (Sep 21, 2006)

Fill a small ziplock bag of rubbing alcohol. Throw the pads in there. Let them sit in there for a day or so. Take them out, hold them over the stove with some sort of metal tongs of your pleaseing. Burn the **** out of them. 

Done.


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## Ratt (Dec 22, 2003)

juan pablo said:


> ..... I have read 2 methods, bake in the oven or using Acetone. Any improved methods? I figure I may as well give it a go and use them on my trail bike.


I had grown too lazy to wait for the baking times. I've just cleaned with brake cleaner and cooked over an open flame (stove or torch). You will see the pad flare up momentarily as the crap burns off then settle down. Sand the resulting glaze off the pads, clean the rotors (I prefer isopropyl alcohol here), and bed-in the brakes again. I've been 90% sucessful using this method on metallic/sintered pads not sure about organics.


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## EDizzleVR6 (Oct 4, 2007)

I have a can of muc-off brake cleaner, i ride alot of muddy conditions and my brakes are in great condition just takes one or two sprays to the rotor and caliper/pads they run smooth like new


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## juan pablo (Jan 17, 2007)

Cheers for the tips. I have always used Vodka on my rotors but wasnt sure about the calipers. Last time I cleaned the pistons I used and earbud and when clean dabbed some mineral oil and pushed them back, cleaning up when done. Its time to do a full clean and bleed boy I cant wait.
I will try clean the pads since I got nothing to loose, if they come out ok I will try them in my trail bike.


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## ihatepedaling (Jul 26, 2009)

XSL_WiLL Use Shimano mineral oil or silicone grease/spray.[/QUOTE said:


> Yes on mineral oil no on silicone grease/spray. Its just too slippery and its kind of chunky stuff. I've found it contaminate lines and have bad effects on fluid flow. Also you don't want the piston to be too slick. The seals in calipers are square so they act as a suito spring. One edge graps onto the piston and helps it go all the back into the caliper. A piston that is too well lubed won't go all the way into the caliper.
> bottom line: clean pistons and put a tiny drop of whatever fluid is in the brake on the piston.


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## NorKal (Jan 13, 2005)

juan pablo said:


> I have always used Vodka on my rotors


Don't use Vodka...that is for drinking. Rubbing alcohol is better.


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## snow-man (Aug 19, 2004)

Agreed, toss the pads and buy new ones. If you REALLY want to you can sand them a bit but don't expect great results.

As for disc cleaning...Alcohol, or disc cleaner works just BE SURE to BURN them after applying that stuff.
Take a lighter or blow torch, etc. to them and burn away any residue.

I dunno about sanding down your disc...that doesn't sound like a good thing. :skep: 

That should do it


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## DeadlyStryker (Feb 12, 2005)

I got a rear brake that seems it has lost some braking power. The pads are still good, and the I don't know what to look for on the rotor. As far as I can tell there is nothing wrong with them. No oil/contamination I can think of. 

Should I burn the pads to remove any possible residue (like chain lube)?

Can someone elaborate on scratching the rotors to get them to re-seat to each other?


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## Jim311 (Feb 7, 2006)

I have had fairly good success with brake cleaner. After that, use a propane torch on them and heat them up until they get good and hot, but don't go insane. It will burn off just about any crap on there.


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