Bearings are filled with grease, the chain should be oiled or waxed, and hydraulic brakes use mineral oil or DOT fluid. But if any of these found their way onto your brake pads or rotors, that’s pretty much the end of their performance. You’ll likely also find that your brake pads lose that matte surface and will become shiny or glazed. With the brake pad clamped in something that won’t set ablaze, quickly swipe a flame from a torch over the braking surface. If you’re still lacking power, and you can’t shift the squeal, then you know it’s time to replace your pads and rotors.