Mountain Bike Discs?

My rear disc brake has suddenly stopped being a effective compared to my front. i think the pads may be contaminated with oil or grease, Do the pads need changing or can they be cleaned with something?
i have already tryed isopropanyl alcohol to no avail.

Mechanical Disc brakes, tryed sand paper, probably wasn't fine enough, does baking them in the oven work, as i have heard that is good?

Hey Petrol,

Ya, once you get any oil or grease contamination on your disk brake pads you should change out your pads, because the pads are ruined forever! Remove your old pads and clean the rotor and brake caliper with rubbing alcohol or non chlorinated automotive disk brake cleaner then air dry. Install your new pads and bed them in. Good luck.

Kimber

You can try one more thing... lightly sand the surface of the pad, and make sure you wipe the disc down with alcohol.

If this doesn't work (and it isn't an adjustment problem) you'll need new pads.

EDIT- Make sure that when you sand the pads you use aluminum oxide (white in color) no greater than 100 grit. Lay the paper on a flat surface andrun the pads over the paper only until roughened. Sorry for the earlier omission of this info.

Just to add to what Mirage.. has posted, You didn't mention if the disk brakes are hyd. or mech. If they are hyd. you might have to re-bleed them as you might have an air bubble (do they feel soft or mushy when used?) trapped in them. (was the bike upside down lately?) Another issue if hyd. might be dirt in the check valve not allowing you to build line pressure.

sounds like you need to sand your pads a little, ive had to do this after accidently getting a lube on them and even after a sand you never really get back all the stopping power, might wanna just invest in new pads.

Just buy some new pads before you burn your house down. The pas aren't that expensive.