My 2009 SLX brakes have been superb from new but I put a new (2nd hand) 180mm rotor on the front, complete with appropriate adaptor – having had a 160mm on there originally. I noticed on the last ride that as you pull on the lever, it has a notch, bump, stumble – not sure how best to describe it – in the middle of the lever stroke. It works fine, but there's a definite pull > stop > pull in the lever travel.

Any suggestions? Sticky piston, pads, rotor issue, muppet mechanic?

I meant to post this earlier as I need to suss it tonight before I ride in the morning… so no pressure then 🙂

cheers

look underneath when you pull the lever – does the 'notch' feeling co-incide with when the roller on the servo wave thingy moves direction?

I sometimes notice this on my XTs, but only when in the garage – not noticed on a ride.

heading for the garage now, matthew – thanks for the tip. I noticed it on the ride though – but it definitely happens when it's stationary.

Spray some wd40 into the bottom of the lever, it is the roller cam for the servo wave sticking

I've just GT85'd the bottom of the lever, so will see how that goes, but have taken the pads out too. They still have a couple of mm wear left (is that ok?) but one of them appears to have worn at an angle, so it resembles a wedge. It also has a lip to the top of it – where it's worn significantly less – only about 0.5mm, but it's standing proud of the rest of the pad.

I think I'll replace the pads anyway, but any ideas what's caused it?

thanks again for the help so far.

Sounds like the pad is hanging over the edge of the rotor a bit, are they shimano rotors? Worth dropping the wheel and pads out and squirting some gt85 into the caliper and then getting an old toothbrush in there to have a bit of a cleanup.

Yeah – Shimano RT75 6 bolt 180mm with Shimano adaptor. I'll go scrub the caliper and let it dry off before dropping some new pads in. Do you think it's the deformed pad that's caused it or still something on the servo bit of the lever?

[thicko] Are the pistons supposed to have a line across their leading edge? They both have it on mine, so I'm guessing so, but I've never really looked / noticed before… [/thicko]

cheers again.

Ok – heaps better for that, thanks. I reckon it probably was the servo wave thing sticking – it certainly appeared to be at the right point of the stroke. So saying, the new pads and the good scrub down below won't have done it any harm either. Thanks guys – really appreciate the suggestions.