Disc brake issue.

[Trevrev]

After just over a year of having my bike i changed the disc brake pads (Hydraulic). Out came the old, and i replaced like for like ( Resin ). I'd never had an issue until i changed the pads. After about a month, they started squealing like a monkey in pain, and not really working very well. Took them out assuming contamination, cleaned all through with IPA alcohol, roughed up discs and put another new set of pads in. After a few weeks of perfect brakes, the same thing happened. As before, cleaned all through, and another more expensive set of pads. You guessed it, same thing happened. All noise and no brakes! A guy near me works in a bike shop, so i approached him and he took my bike away to have a look.
He cleaned the whole system through, did a re-bleed, and put sintered pads in this time. Roughed up the discs and all was great. Now it's happened again.......All noise and no brakes! Matey is on holiday, so i'd thought i'd pick the brains of my fellow cyclists.
What is happening, and what can i do.
Everything was fine with the original Pads that came with the bike.
There are no leaks on the hydraulics either.
Any help would be very grateful.

Also used, muc off, brake and clutch cleaner. I even boiled one of the sets of pads.
Could the discs be the cause of my problems? They look fine!

Cheers.............Trev.

 

[PK99]

After just over a year of having my bike i changed the disc brake pads (Hydraulic). Out came the old, and i replaced like for like ( Resin ). I'd never had an issue until i changed the pads. After about a month, they started squealing like a monkey in pain, and not really working very well. Took them out assuming contamination, cleaned all through with IPA alcohol, roughed up discs and put another new set of pads in. After a few weeks of perfect brakes, the same thing happened. As before, cleaned all through, and another more expensive set of pads. You guessed it, same thing happened. All noise and no brakes! A guy near me works in a bike shop, so i approached him and he took my bike away to have a look.
He cleaned the whole system through, did a re-bleed, and put sintered pads in this time. Roughed up the discs and all was great. Now it's happened again.......All noise and no brakes! Matey is on holiday, so i'd thought i'd pick the brains of my fellow cyclists.
What is happening, and what can i do.
Everything was fine with the original Pads that came with the bike.
There are no leaks on the hydraulics either.
Any help would be very grateful.

Also used, muc off, brake and clutch cleaner. I even boiled one of the sets of pads.
Could the discs be the cause of my problems? They look fine!

Cheers.............Trev.

How are you breaking in the pads?

"Arrest the Squeal Before it Begins

Wayne says to break in your disc brakes with a series of very firm stops from a reasonably good speed before you get out on the trail. This properly deposits the pad material on the braking surface of the rotors. Typically, most riders drag their brakes lightly around every corner in the trail, as well as down easy descents. Lightly dragging a new set of brakes is a perfect recipe to create brake howl - which is why you see so many cross-country riders with noisy brakes."

Chapter and verse on both cause and remedy here:


http://www.pinkbike.com/news/Tech-Tuesday-Silence-That-Squeaky-Disc-Brake-2011.html

 

[sight-pin]

I was a commercial vehicle mechanic many many moons ago. We used to chamfer the front brake linings on some vehicles as a similar problem used to occur.
If brakes are squealing, it's because the pads are bouncing... so to speak,
it may be worth chamfering at least the leading edge to a bevel of each pad if your at your wits end with the noise.

https://www.google.co.uk/search?q=chamfer brake pads&espv=2&biw=1060&bih=677&tbm=isch&tbo=u&source=univ&sa=X&ei=3DgYVPnIIqWg7Ab51IHwAw&ved=0CDoQsAQ
Also here http://ebcbrakes.com/articles/squeaky-brakes/

 

[Globalti]

If the brake works okayish but makes a loud juddering squawk as the bike rolls to a stop, the problem is definitely contamination.

 

[Trevrev]

If it is contamination, how come it's only happening with the new pads. The originals were spot on.
It's getting really annoying now.