Poor performing XT brakes - Solved

[davidj]

My surprise Christmas present to my self, imagine my surprise when I sobered up and realised I had bought another bike LOL, is coming on strong.

I have upgraded the Deore brakes to used XT-M785, new hose for the rear and both fully bled. New Ice tech rotors and I have great feel at the lever.


BUT.....

They don't want to stop me! I bled the brakes with pads removed, I cleaned the rotors with disc brake cleaner. I have subsequently flatted the pads with Emery cloth and wiped them down with disc brake cleaner. Performance is still poor and now they squeal like a squealing thing! They are Shimano Resin pads with loads of life left.

I swapped in some Shimano metal pads and they had good bite, so it is the pads that are my problem. Any ideas what I can do to improve the pad performance? I don't want to spend £40 on new metal pads as these are temporary brakes whilst I steel myself to the cost of some XTR 9000 brakes.

 

[Madmax1993]

Re:

Sounds like the pads are deeply contaminated/glazed. If scrubbing with Emery and brake cleaner isn't doing it, there's not much you can do. Time for new pads. Normally pads can be acquired for less than £40 per pair if you know where to look. I bought a pair of heat sink branded Shimano pads for £13 on eBay, so that would be £26 for both front and rear, and I believe they're some of the dearest pads to get. Also, you can run those brakes with non-heat-sink pads as well.

 

[T'boo Ted]

Re: Poor performing XT brakes

There is a thread on mtbr about 785 brakes and how the pads "go off", I know mine surely do.
On one bike they were great, then over a winter the bike wasn't used for months and I used my other bike (also with 785's), when i jumped back on the other bike, nothing on the rear. New pads worked, but as that bike doesn't get used a s much, ended up with both ends fading.
Take it out for a good ride, first couple of downhill are sketchy, but if I get a good enough run, they come back fine. But it needs to be ridden regularly.
Oh and they howl and carry on too until they come back to usefullness.

 

[davidj]

Re:

Looks like you are onto something T'boo, they are now stopping me. I can even lock up the back wheel- still sounds like I am abusing a goose but they are getting there.

 

[ishaw]

Re:

I've got some magura mt6 that do that. A real pain and loud for ages, and poor braking, just about come back by the end of a 2 hour ride. Rinse and repeat each ride, though a fair gap in between. This is with new pads and clean rotors.

 

[drcarlos]

Re: Poor performing XT brakes

The 615 brakes are actually better rated than the xt ones believe it or not. Anyway I find that once the pads are about half worn in my shimano brakes they are terrible. I’ve tried both resin and semi metal and have just moved onto sintered pads on the trail bike and I’m going to try the same on my cube too, they are supposed to last longer in the mud and rubbish conditions here. The resin pads don’t last 5 minutes. There are plenty of decent pads that don’t cost £40 a set. Noah and Theo or mardychilli on eBay both do a bikes worth for less than £10 and I know that the mardychillis semi metal pads work well so I’m fairly confident in their sintered pads, well enough to buy another set for my cube before I’ve used my kona again.

Carl.

 

[davidj]

Re:

I have given up! Some Uberbike Race Matrix pads ordered.

 

[davidj]

Re:

Uberbike Race matrix pads have solved the problem, no more squealing and solid stopping power. £17.98 for 2 pair delivered direct from Uberbike.

 

[elite504]

Well done for getting there! And good info.
I have tired and given up now with all my Shimano brakes. Much as I love their stuff, as you describe, they sound like a wounded goose. All bikes slowly migrated to hope.... easy to look after and bleed.