Glazed brakerotors

[Tomstr]

I'm placing this here as it could be an MTB, cross, gravel, touring or road topic. Mods, please feel free to place it somewhere else if needed.

It looks like the Hope floating rotors I have are glazed. Their braking performance is only so-so and in the wet the squeal enormously. Removing glaze from motorbike and car rotors seems like a simple affair by just cleaning and sanding them with a light grit but I'm curious if anyone here has ever done it or knows a method to recommend.

[sungod]

glazed rotors would be odd i think, usually just contaminated, use solvent to get them totally clean - then if something has got melted onto them you should be able to see it and decide if mechanical removal really is needed

glazed pads more likely, but i's start by trying just degrease

if still no good, use very fine abrasive, then fully degrease as well, make sure abrasive is flat and applied parallel to the pad face

[gtinut]

like sungod said, just use alcohol with lint free rag.

[NovemberDave]

Most rotors will moan and groan in the wet but have you tried using a squeal stop compound behind your pads (between the pads and pistons)? Doesn't last forever but takes two minutes to do and works incredibly well for as long as it lasts. I use red boat trailer bearing grease.

Alcohol and a clean rag do great for occasional cleaning of the rotor itself. After really nasty rides or other particular abuse, a scrub with an abrasive pad works well. Follow that up with alcohol and clean rag, and then you'll need to do a quick re-bed.

[Tomstr]

Thanks for the advice guys. I thought it was strange too but as the rotors are only 1.6mm thin heat buildup can be real.

I'll give them a good clean with alcohol and take the pads along with it. The grease on the back of the pads makes sense too, works great with cars etc. I have some copperpaste/antiseize around, that should do the trick.

If that doesn't get them braking well I'll get the Mavic sanding pad out. Should work well for discs too.

[mattr]

I use red boat trailer bearing grease.

Check that it's compatible with the seals. The whole DoT/Mineral/LHM/whatever issue applies to grease on the other side of the seal as well.

Copaslip does a pretty good job and doesn't affect either type of seal.

And you can probably exceed the liquification point of most greases in a braking system, so you'll get runny grease exactly where you don't want it.
Copaslip is "better" but you may still get some of the components melting, not sure what the make up is of most copaslips, the one i have now pretty much drys out after 24 hours and is good to several hundred degrees, no greasiness left, the last stuff i had was actually a copper loaded grease, so stayed greasy forever and you'd get the grease running out at high temps (but leaving the solids behind).

If that makes sense.

[Tomstr]

+1 for Copaslip. It's widely used in the metal industry for good reason.

A lot of bike grease products are rebranded from the metal industry anyways so it makes sense to see what the hardware store can supply.

[jfranci3]

If you've degreased the rotors, most like the pads are fouled. Toss the pads in your oven @ 400 deg for an hour or so. Reinstall. They should be fixed.

[NovemberDave]

I use red boat trailer bearing grease.

Check that it's compatible with the seals. The whole DoT/Mineral/LHM/whatever issue applies to grease on the other side of the seal as well.

Copaslip does a pretty good job and doesn't affect either type of seal.

And you can probably exceed the liquification point of most greases in a braking system, so you'll get runny grease exactly where you don't want it.
Copaslip is "better" but you may still get some of the components melting, not sure what the make up is of most copaslips, the one i have now pretty much drys out after 24 hours and is good to several hundred degrees, no greasiness left, the last stuff i had was actually a copper loaded grease, so stayed greasy forever and you'd get the grease running out at high temps (but leaving the solids behind).

If that makes sense.

Tons of sense, thanks for the tip. Haven't seemed to reach that heat but absolutely no doubt could.

[TheKaiser]

I use red boat trailer bearing grease.

Check that it's compatible with the seals. The whole DoT/Mineral/LHM/whatever issue applies to grease on the other side of the seal as well.

Copaslip does a pretty good job and doesn't affect either type of seal.

And you can probably exceed the liquification point of most greases in a braking system, so you'll get runny grease exactly where you don't want it.
Copaslip is "better" but you may still get some of the components melting, not sure what the make up is of most copaslips, the one i have now pretty much drys out after 24 hours and is good to several hundred degrees, no greasiness left, the last stuff i had was actually a copper loaded grease, so stayed greasy forever and you'd get the grease running out at high temps (but leaving the solids behind).

If that makes sense.

Tons of sense, thanks for the tip. Haven't seemed to reach that heat but absolutely no doubt could.

My experience is that pad material is quite porous, and when contaminated with lubricants they will be contaminated down pretty far into the pad material, not just on the surface. Even degreasing/sanding is inadequate to get rid of the contamination, and so the only option is to try to burn it out of them in the oven or with a blowtorch, the success of which is not guaranteed. In addition, many models of brakes have holes in the pad backing plate where the pad material protrudes to the back side of them, providing a direct conduit between the front and back surfaces of the pad.

It sounds like you guys have been successful so far, but it just seems risky to be putting a grease or oil containing compound on the back of the pad, where it could be drawn through holes in the backing plate, or around the edges of the backing plate, and then absorbed into the pad material. Particularly when the material will be subjected to heat that will thin it, and vibration what will speed its journey. If it works for you, more power to you, but I have dealt with enough lubricant ruined pads in my life to avoid any risk of contaminating them like they plague.