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My Brain Hurts!
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697 Posts
Discussion Starter · #1 · (Edited)
Howdy!

I have an issue and am looking for advice. When I picked up my Rainier, all seemed okay. However after riding it the other day, I noticed what seemed to be grease on the front rotor.

So today I cleaned the rotors with a dry cloth and after a downhill braking the front rotor shrieks like a banshee!

I read through the brake forum and found alot of cool info, and the most likely thing to do is re scuff the pads, I guess. However if they did this o this stop, what is to stop the same issue from re appearing on the next hard, or long downhill stop. I mention the type of braking as I am assuming there was a fair amount of heat built up on this type of braking.

Any ideas, short of re scuffing the pads? I do not think brand new brakes should have grease on them, nor should the yowl after one long stop on a clean rotor. (BTW, Hayes Mechanical brakes)

Thanks!
 
G

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Once you get grease on the pads it works it's way in and as a rule it's new pad time. You could try disc brake cleaner or white spirit(on pads and rotor). But grease is almost always new pad time.
 

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My Brain Hurts!
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697 Posts
Discussion Starter · #3 ·
Thanks for the reply, I have to wonder how the grease got there in the first place....nothing that I ever did...oh well, pads aren't that expensive.....
 
G

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ProfGumby
Before fitting new pads give the rotor and the inside of the caliper a "really"good clean as the grease will have burnt onto the rotor. Also check that your hubs are not oozeing grease from the wheel bearings as this could be the original cause of the problem. If it's a new bike they may have over filled the wheel bearings.
 

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I've heard it said that it can be worthwhile to bake contaminated pads in an oven, or set a blow torch on them, to rid them of oils. I can't verify this as I've never done it myself though I probably would if I needed too before replacing them.

Can anyone verify or refute this method?
 

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6,762 Posts
It can work okay for oil....

but grease is another story. Things like chain lube, fork oil etc. don't have that high of a resistance to heat so they burn off at realatively low temperatures. Most greases on the other hand have a considerably higher heat rating than an oil. Most ovens aren't capable of getting hot enough to burn the grease out. You can try it and see if it works, if the grease is light enough you may be okay. Also greases and oils do not completely burn off. They leave residue behind so your pad is still contaminated. Depending on the grease or oil those residues may still cause squeeling and reduced braking power. You just never know. If you want to try baking go for it. It won't hurt to try and may work just fine. But I'd order a spare set of pads anyway and have them on hand or on the way. That way if baking works you've got a spare set which is not a bad idea anyway. If it doesn't then you've got the pads on hand to swap out.

Good Dirt
 

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Dirt Deviant
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3,694 Posts
I can verify that burning off the pads with a small blow torch works great.
I actually got em so hot the pad material was glowing red. I waited until they stopped smoking from the pad surface and let em cool down, reinstalled and BAM!!!!!! 100% braking power.

At first I was concerned that torching them would kill the epoxy bond that holds the pad material to the plate, but that wasn't the case.

NOW, keep in mind that you don't want to heat the plate, but the pad material itself. Watch where the smoke is coming from.......if you see any smoke come from under the pad, let off with the torch because you are burning the glue that holds the pads on.
Only get em hot enough that smoke is coming from the pad material. not from under it.

I figured I would try this before getting new pads.....if it didn't work, no loss and I prolly needed new pads anyways.
But it works great and I've put a few hundred miles on the pads that I burned off with zero issues.

Now when I get new pads on any of my bikes I lightly burn them off even when new. You'll be suprised how much faster they will bed in, and I have seen small amounts of oil or something burn out of brand new pads when I heat em up. I've done this with a couple sets of new pads now, and the bed in process seems to be cut in half-ish.
 

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My Brain Hurts!
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697 Posts
Discussion Starter · #9 ·
Well,

Short of torching the pads, I tried everything I could think of and a lot of the tips here. The pads do not squeak as much now and the rotor is shiny clean like it's rear counterpart, but the brakes still squeak and I have something muffed up with the adjustment, as there is about half the stopping power up front as there should be. So I rode it over to the LBS and said, "Fix it"

I am getting new pads installed and letting them have a go at it. Maybe there will be some consideration as the front brakes were greased up from the LBS, not me. This bike only has about 5 miles on it due to the brake issue....I know stopping is for wimps, but really, the brake should work from the shop/factory.

I also checked to be sure the hubs/bearings were not spitting grease too.

Ah well, I consider it a lesson for me on disk brakes, and a lesson on the stupid little things one should look for when buying a new bike at the shop. When buying it, I tried this bike out on a stationary trainer so never used the front brakes other than to hold the bike steady in the trainer. (There was still snow and ice out when I tried it out. ) So I based the front brakes performance on locking up an non rolling wheel. But really should a guy expect to find grease on a rotor of a brand new bike?

Never again, ride it in the real world to see what's what....
 
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