OK seriously my disk's..

ddraver

they are really startin to pee me off now

Ive put new pads in, pushed the pistons well back inmto the housing, put new springs in etc etc, greased the bolts squeezed the brake lever really hard tightened the bolts up turn by turn

BUT THEY STILL RUB!!!! AAARRRRGGGGGHHHHHHH!!!!

I must be doing something wrong but for the life of me i can't get it, they ruined my ride yesterday

they re Avid juicy carbons and each end is as bad as the other, could the disks be out of true, they re pretty new (1 month) or do they need a bleed, ive sdqueezed levers at the wrog time and everything, it took tikme to get used to what i'm not allowed to do

dave

ddoogie

Do they always rub or is it intervals? The latter would suggest a warped disc. The former either means the disc is sitting out of line or the calliper is out of line.

Did they always rub?

ddraver

they seem to, I do my best to readjust them but they never properly run free....

S_J_P

So, do they rub all the time or just once per revolution? (Your answer wasn't too clear).

Put the bike upside down, hold a piece of paper or card behind the caliper and look through the gap between the pads and the rotor. Spin the wheel slowly to see whether the disc seems to get nearer to one (or both) pads. If it does then the disc is warped. Make sure the six rotor mounting bolts are tight, and that there's nothing jammed between the hub and rotor. If not, then you'll need to either straighten the rotor, replace the rotor, or live with the rubbing.

IIf the rotor touches one pad all the time, then the caliper is still misaligned.

When you went through the process of clamping the brakes and tightening the securing bolts, you did tighten in the correct order? Nip-up the IS adapter to the fork (if you're using the adapter), and then tighten the Post-Mount bolts with the brakes on. Do it with the bike upside down so that you're not deflecting the disc with your weight. If you're still finding that the pads are rubbing on one side, then you may need to place shims on the IS adapter.

ddraver

I'd love to S_J_P but they avid ones don't use shims they use this (&£&$£"^&*%) CPS system of concave bolts etc to prevent you having to face the frame etc etc

they seem to rub all the time at the moment but when they ve been better thy have seemed to touch once every revoloution but i'd thought well they re new so they ll be OK....perhaps not

S_J_P

What forks?

The Juicy brakes are Post-Mount with an IS adapter IIRC, so the Post-Mount concave bolt alignment can take up so much slack. If you have IS forks, then you can still shim the fork/adapter connection too.

ddraver

Yep Rebas so IS

that sounds interesting...how would i know if they need to e shimmed out?!

btw...it sometimes looks as if the pads are being pushed away so that the top moves less far that the bottom of the pad (if you see what i mean) could that be the problem, Its an old frame too.....

S_J_P

Basically if the outer-pad touches, then shimming the fork/adapter interface with a 0.25mm washer will move the whole adapter/caliper outwards by 0.25mm. If the inner pad's touching, then the assembly is already too far out

Were the brakes professionally or self-fitted?

If self-fitted, I'd remove the rotors again, clean the hubs and discs mating surface, and reaffix them just to be sure they're not compromised in any way. Whilst they're off, I'd lay them on a piece of glass or other flat surface (e.g. worktop) and check whether they're warped.

ddraver

so you put a shim straight onto where the whole assembly bolts into the fork?! or where the CPS bolts attatch to the is adapter?!

and they were self fitted yes.....

S_J_P

The shim (washer) fits between the fork mounting block and the IS adapter. It may be an idea to fit a 0.5mm washer (or two 0.25's) to both the top and bottom fork mount and then use the cap'n'cone on the caliper to back-off the adjustment.

It may be useful to check the park tools site for information on setting up disc brake calipers too.

ddraver

sorry....so th shim lies right next to the fork.......can't visualise it

S_J_P

That's right, right next to the fork (between the fork and the calipers adapter)

ddraver

cheers S_J_P will have a look tonight

S_J_P

Good luck!

Rockhopper

I had a similar problem with my Juicy 5's but it turned out to be two problems. The first one was that the outer edge of the disk was actually rubbing the caliper itself. Easily cured with a few washers.
The alignment problem took a bit of fiddling. Firstly i put some coppa slipon the domed washers so they would slide over each other easily. The center the caliper as it says in the instructions. Loosen the bolts a little and spin the wheel. Give the caliper a little tap at one end, if the rubbing increases then give it a tap the other way. Gentle taps are needed till the noise stops. Then nip up the bolts.
Of course if the disk has too much run out this won't help!

ddraver

OK will have a go at that rock hopper

They re better now, the back one needs some washers i think, and the front one is the disc out of true...i think

The whole system needs a bleed and stuff though too really..think i might let a shop have a play