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Changed the Magura brakes on my Dale Jekyll to Zee's, as struggled to get them working. Still didn't work. Took the discs off, as per a previous thread on them being blued from heat with the Maguras in Spain. Found they were annealed from heat, so scrapped them ( metallurgist inspected them, luckily my mate has them as a customer !) Fitted a larger 203mm disc on the front and the usual 180mm rear, both Shimano Zee solid ones. Tried bedding them in , with a few speed stops and water ( when cold) . Changed the pads for Uberbike white Kevlar pads. Gone back to the sintered shimano with fins. Just cant seem to get any bite , whatsoever. Get friction, on long braking, as the fins get hot. Turning into a bloody nightmare this bike. Other bikes with Deores, are just so fantastic. Any help on breaking these in, before I just break the sodding bike. Seems I also have no 3 freehub now starting to wobble again. Not bad for a 5 month old bike......
so you have Zees, new, freshly bled, with new clean pads and brand spanky new clean rotors and after a few mins 'bedding in' of the pads they dont
a. work
b. set the world alight
c. match your deores
get deores?
It sounds like contamination. If the pads are fresh I would wonder about the o-rings/seals in the caliper.
Try this:
-Pads out
-wheel in
-put some bogroll/kitchen roll over the rotor, and rotate so that the covered section is inside the caliper
-zip tie the brake lever to the bar, so that the brake is "on"
-leave it overnight
If the tissue has any oil on it the next day, you need new calipers.
The brakes are all brand new. The discs are brand new, the pads are brand new. The problem is complete lack of bite on them. I am thinking of just going up a big bastad hill and hammering down through mud and grime and grounding the sods in........
My Zee's were pretty good out of the box, the Saint's before them had a leaking seal and so would give no power at all even on brand new pads, as they would contaminate each time. Took ages to figure out.
Rough the discs up with sandpaper?
I'll have a go with some emery cloth. Been through all this with the Magura discs, although thy were cooked.
Also worth getting a bleed funnel and purging any air through the lever, you'll usually release quite a few bubbles, and firm up the lever feel on a new set of brakes(even though they're supposedly pre-bled). If you have air in the system, it can rob you of quite a lot of bite and feel.
I had a new set of Zee's and out of the box the rear brake was pish. Lever would pull right to the bar. Two bleeds later and it's fine. Not sure why but air does seem to get trapped somewhere. As Coatesy, I used a bleed funnel, but I also take the pads out and pull the lever all the way to the bar, or as close as I can, and then cable tie the lever to the bar and leave for 24 hours, just returning to tap the caliper and hose periodically to encourage the bubble to the top.
Solid rear brake now which matches the front. Great set of brakes.
Cheers guys. I have the funnel, but have found by taking out the bleed screw on the lever and turning up the clamp, so its vertical, means I was able to 'de- bubble' the brakes. Must admit its not as solid feel wise as the Deores. I have some oil, so I'll give them a bleed and reort back later !!
If the problem is getting bite, just do 20-30 stops from 20mph or so using one brake at a time. I'm not convinced water etc. will really help. Roughing things up with sandpaper could help but shouldn't be necessary if everything is new.
Bleeding will only improve lever feel, not power.
Zees do have more lever modulation than other Shimano brakes so the power is not instant. My rear Zee also needed much more attention bleeding - something like 15 minutes of gentle bleeding back down through the calliper until one single large bubble popped out - all good since.
Well I bled them with assistance of mini TJ on the lever and fund a few microbubbles on the front, nothing out the rear, except right at the start, so guessing its just the air in the nipple. Used a half funnel full per brake to bled. All came out chrystal clear, as you would expect being new. Then emery clothed the discs and wiped with dry clean tissue paper and went for some stoppies. Does feel a bit more biting now. Found the front was juddering as if gripping and letting go. Not like the pads were contaminated, as they aren't. Fins on the pads got bloody hot. Guess I need to take it to Wales and give it death and that should grind them in a bit better.
Thanks for the help everyone, feel a bit more confident I'm making progress.