Bicycle Mechanics - Shimano XTR M975 hydro disc adjustment question

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GlassWolf
05-09-08, 10:18 AM
I just put together a new wheelset, with some Aztec rotors (160mm) and when I freely spin the wheels on the bicycle, while on the repair stand (quieter to listen for issues that way) I hear the pads rubbing on the rotors.

How do I back the pads off from the rotors slightly on an M975 XTR caliper?

details:
'06 Trek Fuel EX 9.5
Full XTR group
XTR Dual control STI levers (pretty sure)
wheel sets:
Mavic Crossmax SLR wheels, Maxxis UST Larsen TT 2.0" tires, XTR rotors, XTR cassette 9sp
Vuelta Team SL ATB wheels, Maxxis Holy Roller 2.2" tires, Slime SmartTubes, Aztec 160mm rotors, SRAM PG-990 cassette

Is there a simple adjustment for this, or will it involve re-bleeding the brakes?

http://www.glasswolf.net/misc/trekbrake.jpg

thank you

bac
05-09-08, 10:22 AM
How do I back the pads off from the rotors slightly on an M975 XTR caliper?

This has worked with my disc brakes.

First, pop out the pads. Then, using the round end of an aptly fitting open-end wrench, gently pry back the piston a bit. Reinstall the pads, and check again.

Good luck!

... Brad
GlassWolf
05-09-08, 11:07 AM
by round end, you mean the closed/boxed end of the wrench, I assume?

thanks

GlassWolf
05-10-08, 09:23 AM
any other thoughts folks?
I'm a bit nervous about shoving a wrench into the caliper and trying to bend/spread it..
I can't be the only person who's ever had a set of hydraulic brake pads rub on a rotor.
JTGraphics
05-10-08, 09:44 AM
Am I wrong but aren't the pads floating in the calapers like a car's disc brake. If thats the case pads are prone to rub at times as soon as you apply brakes as the pistons retract the pads don't go with them.
But are floating in a small space and may at times rub slightly no matter what you do.
If the pads were directly attached to the pistons then I could see were you might be able to get clearance all the time but they are not , is this correct?