Help Cleaning Disk Brakes

TokyoLiving

Maximum Pace
Dec 9, 2015
590
250
93
53
#1
Hi, anyone have any suggestions for cleaning fluids for rotors and cleaning the pads for disk brakes? I have read isopropyl alcohol works for rotors. I have a strange squeak coming from my front brake.

Don't want to annoy the h$ll out of my riding partners with a squeak, squeak squeak... you get the picture.

Thanks in advance.
 
Aug 27, 2012
581
234
73
London, UK
www.macrophotofly.com
#2
As you have guessed the squeak means something on the pad rotor - probably oil based. You don't mention what type of brakes you have Shimano Hydraulic/ SRAM Hydraulic / Other cable

Honest truth is, once you get anything on Shimano pads they are shot. I have been fairly unlucky with at least three Shimano caliper units leaking tiny amounts of hydraulic oil over time (from between the caliper body and the ceramic piston) and if you then ride in the rain that oil gets on the rotors/pads destroying the pad. No idea how they survive in the UK where the roads are always wet and oily. Thought the whole point of disc brakes was meant to be that they were good in the wet!!!
If you have SRAM/Avid etc, the pads seem to be a lot more resilient to contamination.

Anyway, despite reading never to put anything on the brake pad I have been through enough now to try out a few things to see if I can get them back working 100%
Rotors -
  • Take some sandpaper (fine) and give them a sanding - just enough to leave scratch marks perpendicular to the normal grooves
  • Then clean with an alcohol-based cleaner. You can use an alcohol based degreaser but make sure to wash off afterwards.
Pads -
  • Degreasers do not work - kills the pads
  • Alcohol doesn't seem to work (except for calming the rider:D).
  • Soapy water can help remove something on the surface, but the problem with the Shimano pads is that they are porous so the oil is just back in the next layer
  • Continuous downhill with brake applied - this can work if the contamination is light and it gets burnt off. Had 50% success with this on long downhills
My final idea is to get a cooking blow torch and try to heat the pads up to around 300C so it burns the oil off. Have a set of contaminated pads ready to do this but not the blowtorch yet. The risk of this, is delaminating the pad from the metal backing, so would not recommend anyone else trying this.

Basically just buy some new pads....
 
Likes: luka

TokyoLiving

Maximum Pace
Dec 9, 2015
590
250
93
53
#3
@macrophotofly thanks very much for taking the time to write such a detailed reply on disk brake cleaning. This is my first owning disk brakes. I am sold on them. I do happen to have shimano.

I will try it all and as a last resort shell out for some new pads.

Thanks again.
 

wimpy

Warming-Up
Jul 14, 2016
8
2
3
32
#4
Pad alignment and bent discs can also Cause squeaks, ideally you should be able to see a little light on either side of the disc.
 

bloaker

Maximum Pace
Nov 14, 2011
1,550
1,221
433
Miura, Japan
#5
If you are sure the pads are not contaminated....

1st attempt at shutting up brakes... Clean rag & Rubbing alcohol and wipe the rotors down, Remove the pads and hit them with some sand paper . Rough them up a bit. (get that surface glaze off of there)
2nd attempt - do your first attempt but also swap your pads front and rear. - After some wear, I have had rotor/pad combos just not agree no matter what I do. I have swapped the pads and all issues when away.

And then comes the crucial part... you need to re-bed the brakes! If you have a hill near you, this is perfect.
Get up to 30kph or so and brake down to 5kph or so, and repeat, you may experience squealing the first 3, 4 or 5 times, but in my experience after that, they shut up and have plenty of bite.
Be sure when doing the rear so get your weight way back so you are not just locking up the wheel.

I have never roughed up my rotors - just a good cleaning has always worked on my MTBs and cyclosross bikes.