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Discussion Starter · #1 ·
Fellas,

I was bleeding my front '03 XT hydraulic disc brakes and was just about done when the clear plastic tube slipped off the bleed nipple and mineral oil pissed all over the stock Shimano pads and rotor! :mad:

Now I've got a squealing front brake that doesn't stop worth crap. I took the pads out and soaked them in 99% isopropyl alcohol and patted them down in a paper towel. I repeated like 3 times. I also rubbed the rotor as best as possible with isopropyl alcohol. That didn't work. Then I got even madder and pulled out the paint thinner (varsol) and repeated the procedure. That didn't work either.

I just read some posts about sanding the rotor and pad surfaces with fine grit sandpaper. I'll give it a shot again and post an update. In the meantime, has anybody successfully cleaned up spilled mineral oil and ressurected their brake pads and rotors? Or am I screwed and down another $50 for new pads and a rotor? I'll have to mail-order them because the local Shimano XT brake pad market is completely sucked dry.

If it ain't broke, don't fix it. That's an ideology I should really learn to respect.
 

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the rotor is certainly easily cleaned, the brake pads maybe. I have had the best success with heavy duty spray-type brake cleaner available from auto supply stores. the solvents in the brake cleaner are way harsher than the alcohol, and will degrease and dry quicker. I don't know if I would recommend Varsol or other paint thinner type solvents for cleaning brakes, as many of them leave an oily residue. Some have tried burning the oil out with a torch, with varied success ( I felt the brake cleaner worked better for me) ( uhh - that would be with the pads off the bike and on a non flamable surface BTW :D ) Good luck - worse case, you have to get new pads....... and be more careful next time
 

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Yeah, at MX shops the stuff is labled as "disc brake cleaner". It works great. Take your pads out, take your rotor off and spray them down. It helps to "scrub" the pads as well, either sand them down a bit or just use a brillow pad and some soap. Spraying both with the disc brake cleaner will probably be enough, but it doesn't hurt to be a little more thurough.
 

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Shimano sends 2 yellow plastic pad spacers used specifically for bleeding the XT/XTR disc brake systems. Use those the next time you need to bleed and the brakes will be stiffer and you won't be frustrated if you have a little over spill.
 

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Discussion Starter · #5 ·
Update - sanding and IPA don't work

Wow - it doesn't take much oil to contaminate those pads!

I sanded each pad down for a minute or two and sanded the rotor down. The rotor seemed to clean up pretty well. I wiped it down with isopropyl alcohol (IPA) afterwards. I also wiped the pads down with IPA but they didn't look as clean as the rotor. Re-installed and it squealed. :mad:

Took apart again. Got an old toothbrush and washed it out first. Then doused each brake pad in IPA and scrubbed them like mad for a few minutes each periodically re-wetting with IPA. Scrubbed the brake rotor with IPA as well. Then sandpapered the pads and rotors. Still squealed. :mad: :mad:

Took apart again. Went to the bathroom sink and washed pads down with soap and water using toothbrush that I also washed with soap and water. Then dried off and scrubbed the pads with IPA and toothbrush. Then scrubbed the rotor with soap and water, dried, and scrubbed again with IPA. Then sanded them down. re-assembled and they squealed like mad. :mad: :mad: :mad: Fukin filthy little bastards!

So now you know. Shimano XT brake pads contaminated with mineral oil will not clean off using IPA, varsol, or soap and water even with scrubbing and sandpaper abrasion. What a waste of time!!! :mad: :mad: :mad: :mad:

Gentlemen - thank you so kindly for your most excellent suggestions. I will indeed take them under advisement and obtain the necessary brake cleaner solvents to dispatch with this oily compound. I'll keep you posted and hopefully save other people the frustration of a wasted Sunday afternoon / evening.
 

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Discussion Starter · #7 ·
Brown_Teeth said:
Did you use the .99 spray brake cleaner? Its powerful stuff, don't mess with soap... soap/oil on pads + weak solvents means replace. Good luck!
Yeah - I bought some brake rotor cleaner . . . some generic Canadian Tire brand stuff for you Canucks out there. It didn't work. Still squeals.

Brown teeth may be right about soap, which was probably a bad idea also. The brake pad material is sintered so there are lots of microcracks and pores where oil and other residual cleaning compounds like soap can accumulate away from the bristles. I think these pads are pooched. Maybe the brake rotor cleaner would have been enough if applied immediately. But my impression is that the oil would be very hard to pump out completely.
 

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FWIW I've always found my brakes squeal for a bit after cleaning the rotor with Isopropyl. Then it goes away. That's w/o even touching the pads. I'd suggest don't bother sanding the rotor. Just use break cleaner or IPA, sand your pads lightly use some of the brake cleaner and then bake them as the others suggested...But don't go crazy. If that dosen't work just get another set of pads and consider it an expensive lesson.

After all the stuff you've done to those pads if they weren't hosed before they probably are now. Sorry.
 

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Discussion Starter · #11 ·
Monte said:
Toss 'em in the oven....

I have a little toaster oven I use for this sort of stuff. 350 deg for 1/2 hour or so should do it. Mind the smoke though.

Monte
Mmmmm . . . re-deposited carcinogens with your morning toast . . . :eek:

I agree that the pads have been through too much already with soap and other residual solvents to be considered salvageable. My suspicion is that burning oils out will probably leave a messy gooey residue inside the cracks of the sintered pad . . . just like your Mom's casserole dish after a pot-roast. This has been a time-consuming materials wasting debacle. :mad:

I mail-ordered some Kool-stop pads from BC yesterday morning. It'll take a couple of weeks to arrive but it's the safe thing to do when riding unsafe terrain. The idea that some residual oil could migrate out of the cracks in the brake pads and compromise braking in the middle of a DH ride is very concerning. And then there's the possiblity of crumbling or delaminating from the organic adhesive also burning out . . .

Maybe I'll try a propane torch just for fun but I don't wanna rely on these pads for any real riding. The scientist in me is curious.
 
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