HI all,

SLX brakes which up until recently performed flawlessly. However the front is causeing problems.

At the start of a ride, there is little power even with the lever pulled as hard as I can and the squeal is horrific. It gets gradually better into the ride as I am using them, however, once the ride is finished and bike packed away, its back to the same problem on the next ride. I’ve changed the pads which initially helped, before it starting again. They are generally ok after a lot of use.

Could it be the rotor ? If so can you recommend a good way of cleaning them ?

Many thanks.

So the brakes get gradually better as you ride but the problem reappears when you go back out on a ride?

Sounds like weepy seals, common issue with Shimano brakes.

You could try cleaning the rotors but it probably won’t help

A short term fix is to smear some mud on the rotors, the extra abrasion helps the pads bite and wipes some of the crap off the pads and rotors

Really ? Would that not result in a loss of fluid… they still feel fine at the level ? and there does not seem to be any obvious leak.

Shimano calipers do have a habit of leaking a tiny amount of fluid from the piston seal
I could never see my xt one leaking but after having several set on pads fail I changed the caliper and no more problems

hmmm… theres food for thought. Cheers lads.

Simply go for a dry dusty ride to see if there’s a weeping seal…

when I suffered the weeping seal it wasn’t untill the calipers started to heat up that power was lost .The discs usually self clean due to heat.It may be air in the line try taking pads out and heating them up over a gas flame ,if they are contaminated they will smell of burning oil.check that both pistons are equally out and fluid level in resevoir is ok ,bleed if old oil, and or tie the lever back to the bar to try and purge the air out of the line

That’s why I ditched my Shimanos.

Dont want to ditch them as prior to this problem they were faultless.

Dale… totally the opposite. They are rubbish at the start of a ride and kind of “bed in” after 20-30 mins or so depending on how much braking i do.

Contaminated rotors !, more likely to be the pads. Try new pads and before fitting them clean the rotors with some solvent or alcohol. Pads will absorb oil, rotors won’t 😉

Dont want to ditch them as prior to this problem they were faultless.

Problem is, you have to ditch them anyway as the calipers can’t have their seals replaced. The calipers are spraying a very fine mist of brake fluid onto the rotors / pads. If you replace the pads, it will work for a while, but soon the squeal and crap performance will come back.

I’ve got some isopropyl wipes, bring it round you end!