Rear brake noise even when not being used.....

Thanks for looking...
Im at the point where I'll try ANYTHING to stop the rear brake noise on my SC.Blur.LT.
It goes like this: no noise free wheeling, no noise when the bike is off the ground, the brake caliper IS centered over the rotor.
*new brakes (shimano xtr race), new 180mm 6bolt icetech xt rotor, factory resin pads.

The rear brake moans on long descents, I get that, its normal when you ride the brakes... The noise also happens on DH switchback trails when I'm NOT using the brakes! Sometimes when I'm using them and let off, they moan so I tap the lever and the noise goes away. Today it was gnarly at oaks on deer and chutes. I just sanded the pads tonight cleaned the pistons and centered the calipers again.

Anyone gone through this before? I've never had such a PITA issue on a bike before, heck, I wore out the xtr caliper mounting bolt! 8-[

if you have any ideas, I'll take them!

Thank you!:bang:

 

1. Your rotors are bent.
2. Your bike is flexible....like Nastia Liukin

 

Any play in the bearings?

 

a friend of mine had a similar issue, but his was cured by reseating and tightening his wheels and then re-centering the rotor.

 

Some other ideas:
I think I missed if you bled the brakes. (I read they're new, but may be they weren't bled properly)
Could they be overfilled?
May be you have a sticky piston?

 

Rotors are damn near perfectly true (spun on bike using a marker to check runout).

No play in bearings. This is wheelset number 2 that does this. (1st set was mavic, new set is crank brothers iodine 2 2012) I even took them back to CB to check the bearing hub/bearing for play.

Contacted Santa Cruz, they advised me to ditch my hope skewers for shimano or dt RWS, so I bought the RWS alloy skewers....

*IF the frame is flexing, how would I center the calipers, with me on the bike?
*THEY are new brakes, my saints did this every so often too, should I re bleed them? I did cut the lines to fit on install following directions then topped of the fluids on front and rear lines.

Thanks again for any advise! I'm calling shimano in a lil bit.

 

If the rotor is true, then you have a sticky pad. I'd re-bleed the brakes.

 

id ditch the skewers and run at least a bolt on 10mm rear axle, sounds like you have some flex in the rear end

 

Wheel/frame flex combined with a 180mm rotor flexing.

 

also make sure all your pivots in the rear suspension are tightened to spec, if they get loose on the santa cruz bikes your rear triangle will move around a little and make this noise. look on pinkbike tech tuesday as they had a video of how to tighten them correctly

 

I like that! I'm going to re bleed just because I can! I'll also check the pivot bolts. I did remove ruger rear triangle when I bought the frame (NOS) to replace 1 bearing.

I won't be able to use a 10mm t/a because my wheelset won't support it. I will say the noise is WAY better with the RWS skewers than with the hopes.

 

Dbl posted.

 

Just got off the phone with SANTA CRUZ... They want me to try the 4x upper link on my BLT1. It's the same upper link specs but utilizes a solid aluminum block instead of 2ti pieces. He said this has helped with other noises in the past. $20 shipped with all hardware and a guarantee or money back. NICE! Worth the try! I'll keep you all updated.

 

Forgot to mention, in going to big bear tomorrow for the first time! I suppose I'll know first run if bleeding the system and spending 1hr centering my calipers actually helped. If not, I'll put in that 4x upper link and go from there! ROCK ON!

 

Wow, if he would of said that he had Avid or Hayes brakes all you would of read is, "Ditch those POS buy Shimano, buy Magura, Buy Formula...." It's kinda funny the double standard.

It sounds like to me that the brake fluid might be getting hot and expanding and if there is air in the lines it might exaggerate it even more. I would say give em a good bleeding. If that doesn't do it you might have a sticky piston.

 

Classic.. too funny!

 

Actually if he had formula I would have said get use to it. The new formula brakes have no clearance so they always make noise. I know I had the a ns the fix was get rid of them.

 

On my way back from riding big bear... Bled the brakes last night, STILL THERE! Its getting old fast. Guess I'll get used to it until the link comes in. xtrs are too good to give up at this point! On the bright side, yes I did eat sh!t on my last run. Lol

I'll update after link just incase someone else has this problem!

 

Heat the rotor using MAPP gas and slowly rotate the wheel (best done in a bike stand), sweat out any containments and wipe clean with Denatured alcohol. This has worked for me in the past, the trick is to not get the rotor so hot it distorts. Good luck with that.

 

Is it only in corners still?