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I did a frame swap recently and my front brakes are now screeching loud and not as powerful as they were on the other frame. This leads me to believe that I must have gotten some mineral oil or other contaminant on them during the frame swap process.

The problem is that the pads are expensive and they still have a lot of life left on them. But just wondering if it's a lost cause this point to try to clean or salvage them

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    Next time, take the pads out and fit a spacer, and only refit the pads on final assembly? – Criggie Jun 9 '20 at 0:23
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The best approach I've seen in terms of producing non-mediocore results is heat them up with a heat gun until you can see the oil smoking up and maintain that heat until the smoke stops. You want to heat it through and minimize peak temperature, so let that inform your setting and distance.

This can work pretty well but I make no promises what the metallurgical side effects may be. It's an at your own risk thing only. That said it's a pretty common trick and I doubt there's much risk. And of course do this with good ventilation and with the pads in a vise, hanging on a cable, or some other way where they won't need to be handled until cool.

Things like sanding, degreasing etc really don't work because the whole problem is the material has some porosity.

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    I wonder if theres a difference between organic resin and sintered metal - I had to clean oil out of a band brake once, and that worked best with repeated hot air and dabbing. Took a couple of sessions as well - in terms of time spent, simple replacement would have been cheaper had the part been available new. – Criggie Jun 9 '20 at 4:54
  • I’m not sure on the power of heat guns, but you’d need quite some temperature to soften (anneal) hardened steel. To quote Wikipedia on annealing: “The temperature range for process annealing ranges from 260 °C (500 °F) to 760 °C (1400 °F), depending on the alloy in question.” – Michael Jun 9 '20 at 4:58
  • @Michael It's not a steel backing plate I'd be worried about, but an aluminum one or the pad material itself. – Nathan Knutson Jun 9 '20 at 5:35
  • @NathanKnutson Brake pads better be able to take high temperatures. Try calculating how much energy has to be dissipated as heat via friction between the pads and the disk. If I wanted to get mineral out out of some brake pads, I'd have no problem putting them in an oven at 450-500F (230-260C). That would certainly limit peak temperatures. Yeah, I've also cleaned my cassettes in the dishwasher... – Andrew Henle Jun 9 '20 at 16:12
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Burning them with a lighter and sand fairly vigorously with sandpaper seemed to help enormously.

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