I have a pair of M575 brakes linked to a pair of LX (2007 vintage) Dual Control levers.

My ‘issue’ (apart from being slow and using the brakes too much) is that I can not seem to get the front brakes to bite well anymore. I have relatively new pads, (sintered) and have made sure I have aligned the pads, cleaned the discs with white spirit and bled the brakes. I have even taken to sanding the pads (with an electric sander and rough grade paper) to get the ‘glaze’ off the pad surfaces, as they had been squealing for a bit.

Squeal of death has gone, mostly, but I can’t even do an endo in the car park, they are that pony. I have also tried the old tricks like riding through muddy puddles, down big hills to get them hot and bed in, but still to no avail. Back brake seems ok. Both levers have similar amount of pull/reach/movement.

Can anyone think of anything obvious I am missing? Maybe a pad not moving freely?

It probably makes no difference but I am running the brakes on a hardtail with 180mm front/160mm rear.

I think you went wrong when you used white spirit.

White spirit is a bit oily and though ace for cleaning stuff, it will leave a residue on the rotor impairing braking, and probably would knacker your pads.

My first step would be to clean the rotor with Isopropyl Alcohol or muc-off disc brake cleaner (or similar, must be for bikes not cars though) then put brand new pads in and try bedding in from there.

JW, Thank you for that. I think I have used both white spirit and methelated spirits. I hadn’t realised there was anything in them that would make it worse. Maybe I need to buy some proper disc brake cleaner.

Can I try and sand down the pads to get the contamination rubbed out from the top layer of the pad/surface, or is it a total loss? Pads are pretty new.

Meths not as catastrophic but has other additives (the colour for a start!) and allagedly leaves a somewhat unhelpful residue too.

sanding pads may help. This recent thread discussed it amongst other possible solutions. I have not had much luck at this when I once tried it.

Once you have cleaned the rotors get some new sintered pads and bed them in properly. If you dont they wont bite. Do a search for bedding them in if your not sure how to do it.

Takes about 5/6 goes on a hill, job done.

OK, will splash out on new pads and bed them in.

I have bedded them in before, so am happy to do so again (seemed to work before I went and contaminated them…). Doh. 😡

Clean your rotors off the bike, with an abrasive kitchen surface cleaner such as Vim with a scrubing brush and rinse in water.
Repeat.
Then rinse in boiling water from the kettle and leave to dry.
Do not handle with bare hands when refitting.
Fit new pads.
Burn them in.
Job done.

Miss a step and forget it; you are just contaminating new pads and the whole thing starts again.

PaulD

Go for a really muddy fast ride you’ll soon scrape all the crap off 🙂

White spirits oil based so ya never put oil anywhere near brakes,meths,brake/carb cleaner only !.