Today i fitted some Hope mono M4s (that I bought 2nd from the classifieds). After installing them I gave them a good bleed as the back brake had no fluid in it and the front brake was quite cloudy. The back brake had a sticking piston but now works really well, the front brake, however, squeals and I was wondering what to check/clean/replace? Any ideas or tips as to what could be the cause?

New pads and clean the rotors thoroughly

That’s what I did with mine and they purr now.

I’m far from an expert though

Thanks matey. What’s best to clean the discs with? Meth/spirit?

Put some silty mud on the rotor and brake a few times.

Take brake apart, remove pig, cook and eat pig. Job’s a good un. 😛

Sand the pads surface and re bed – its glazed / polished pads IME tht cause the squealing

If it’s squealing, check rotor/pad alignment. Some brakes will always squeal as the frame/fork flexes moving the caliper under heavy load.

If it’s honking, new pads and clean rotor with IPA.

Thanks matey. What’s best to clean the discs with? Meth/spirit?

This is what I was told to use and it seemed do the job.

Isopropyl Alcohol

put mud on rotors

If it’s squealing, check rotor/pad alignment. Some brakes will always squeal as the frame/fork flexes moving the caliper under heavy load.

It’s funny you should say this as yesterday i was shocked at just how much my forks flexed under breaking :-O (Singular Rigid forks)

Just seen this stuff Fenwicks Brake CleanerWorth a punt if I cant get any IPA?

IPA will be available at most chemists or boots etc.

Ok, quick update. I removed the pads, gave them a rub with some wet n dry paper. Gave the discs and pads and good clean with some ipa and put it all back together. Vast improvement! No squeal and an amazing amount of braking power. Thanks to all for the advice. I’m proper chuffed

Mine squeal when wet, isnt this normal?

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