JGLU

My front brakes were doing all good. One day I took pads and rotor out of the bike to clean them, and I accidentally contaminated the pads with grease. Here is how it happened:


I took out the rotor and the pads and started to clean them. When I was cleaning the pads, I accidentally used a rag that had some grease on it and the pads got contaminated. Trying to solve this I cleaned the grease of the pads with a new rag, then cleaned the pads with paint thinner and a brush, then cleaned the pads with a clean rag, and waited for them to get dry.
I also cleaned the rotor with paint thinner and a brush, then with a moisted rag, and finally waited for it to get dry.
I put everything back on the bike. Rode about 15 km, breaking often so to burn in the rotor and pads. They never got to brake as they used to do.
So I took pads and rotor out again. I cleaned the rotor the same way I did before. I cleaned the pads with a dry rag, then sanded them, then cleaned them with a rag. I rode even more, about 60 km, and they still didn't brake properly.


Aftet that, I decided to try new pads. I took pads and rotor out. I cleaned the ROTOR again, the same way I did before. I put in a new set of pads. I've been riding this set for 159 km, and they don't deaccelerate the bike at all. I've been stopping with the rear and the front brakes at the same time: the rear because it is the only one that stops, and the front because I kept hoping it would finally got to work. I could not buy new rotor and pads until today, and I'm going to install them later.


Old pads and rotor had 1750 km, and their thickness was good. The second set of pads were even better, obviously. I have the Shimano RT30 rotor and Shimano B05 resin pads.

Any ideas why the rotor got useless? Thanks in advance

sean.hwy

is your bike 100% cable operated? or is one those hybrid cable and hybrid operated?

Barry2 

I prefer to clean rotors with rubbing alcohol and paper towel.
And I remove them from the bike so as to not pick up dirt on the inside surface from the spokes.
Barry

wolfchild

If your brakes worked good before but they don't work good now, it almost sounds like something went out of adjustment.

JGLU

Yes. It is completely cable operted.

shelbyfv

OP said he contaminated them while trying to "clean." Hopefully the new parts will resolve this. In the future, stick with soap and water or isopropyl alcohol. cleaning brakes

wolfchild

OP said that he already did install brand new pads, cleaned the rotors and it didn't fix the problem, so my guess is that maybe something is out of adjustment.

Leisesturm

Just saying. New poster with username in all caps that starts thread making established members start fighting each other ... rinse, repeat ...

shelbyfv

Yes but he "cleaned" them with paint thinner.

JGLU

Thanks for the link to the cleaning guide.
Nevertheless, I had cleaned rotors and pads with paint thinner a couple of times with good results.
Today I put in the new rotor, burned in for 8km and now the front brake is working very well.

rsbob 

It doesn’t take a new poster to start a fight. Any thread which is longer than one page tends to devolve that way. Welcome to the board!

OP: Even though your best efforts to decontaminate your rotor and pads (even the new ones) have not worked, you may want to consider buying new of each and starting anew. (Leise - that’s is an example of a positive and constructive response. You might want to try giving it a shot.

veganbikes

Always clean brakes with isopropyl alcohol and a clean paper towel. I do hate wasting paper towels but rags can easily be contaminated either straight from the seller (because they are cleaned in diesel) or because we use them for all different things.

jaxgtr

Ummmm .... username in all caps makes someone suspect now? Been around this forum for a while and that is a new one on me.

jaxgtr

And I like the shop towels or a nice cotton towel that does not loose material as you wipe. Brake cleaner is also an alternative as long as it does not have any oil in it, but sticking with Alcohol is always the best option. It's cheap and can be found practically everywhere.

FBOATSB

Had no idea I was so offensive

Mtracer

I wonder if running the contaminated pads on the old rotor might have glazed the rotor surface in some way and affected it's braking, even with new pads. If this is possible, might it be possible to resurface the rotors, perhaps by sanding or similar?

rsbob 

Only for people wanting to disparage others for no reason. Otherwise you are just fine.

Leisesturm

Don't know why you are lecturing me. If there had been nothing but positive and constructive replies to the OP there would have been nothing for me to say. Who the blank gets out the 'paint thinner' to clean perfectly good brake parts and gets grease on them in the process. There is so much power in even crap mechanical discs that it would take a whole lot more than that to make them unusable. Y'all are being played, period. Its sad that even on the basics it's possible to divide youse. Sigh. I tried.

Leisesturm

I said, new user with username in all caps. Does that fit you? Do I need to link example threads? I can.

streetsurfer

Not real heavily experienced with these brakes -cable disc. Did you possibly swap one pad for the other? Were they worn unevenly in thickness, pad for pad? Don't some calipers require the back pad to be adjusted first to just off the disc, before setting the cable operated side?

beng1

Did you try sanding the old rotor with very fine paper like 600 grit or crocus cloth? If you look up the break-in procedures for automobile brakes that have new pads and rotors, there is a very specific way of doing it that results in much better performing brakes than if that procedure is not followed. So just the way you use the brakes after installing new parts can make a lot of difference. Also I would wonder about the brand of solvent used for cleaning brake parts because some of it can be "oily" itself. There is a big difference in run-of-the-mill pant thinner and something like Acetone or MEK in many ways, and all with have different effects on what they are used on. Lastly back in the old days a lot of people used to put their brake pads or some clutch disks on the ground in a pile, pour some gasoline on them and light them on fire and burn the impurities off them, but of course that procedure is at your own risk.

Kai Winters

Well now you know...

Kai Winters

It is likely you didn't completely remove contaminants from the rotor and the new pads are now contaminated meaning neither will offer good stopping power.
I'd replace both rotors and pads. Don't touch surfaces with skin as the oils will be deposited on the surfaces contaminating them and reducing stopping power and maybe giving you the gift of a lovely squeal when braking.
Lesson learned...or hopefully so...time will tell.
Disk brakes are awesome until they aren't...
I clean my disk brakes with a mix of water and alcohol...pads and rotors...I wear latex gloves, when I remember to, to avoid accidental contamination or I'm very careful when I'm too lazy to put a pair on. When my pads get real dirty I give the surfaces a light sanding then clean with the fluid mix, wipe with a clean piece of paper towel then put them back in the calipers. I also clean out the insides of the calipers with the fluid mix and a clean tooth brush just for the calipers.
I run mech calipers, TRP Spyre, on my Aethos and they work great...not the same as hydraulic but fine. Great power but they do require more pull than hydro's require.

JGLU

Thaks for the info on sand papers. Yesterday I was reading about Garnet sandpaper on other threads, but I don't think I can buy it by that name in my country. I'll look for 600 grit on the shops.

DaveSSS 

Isopropyl alcohol is a poor degreaser and usually has 10-30% water - read the label. Mineral spirits, naphtha and camp stove fuel are all better options. 600 grit sand paper is much too fine for sanding rotors or pads. Something in the 120-220 range would be more appropriate. Mineral spirits does not leave a residue - a popular myth.