# hydraulic disc brakes with stuck calipers / Help!!



## heidenspass (Mar 24, 2010)

just got my first mountain bike and rode it once. I have Avid ultimate hydraulic discs. My front tyre wouldn't rotate properly, I took it off and carefully tinkered a bit to see what was wrong. This included squeezing the brake levers. I can visually see that behind the inside caliper there is sort of a nob that is pushing the pad well into line of where that rotor should be and it won't return to a normal postion. Whilst searching the web for help I stumbled upon this "Please be careful not to squeeze the brake levers with the wheel removed as this may dislodge the brake pads & cause a problem." Now what, I think I might have created a problem. Obviously I'm very new to all this and am desperate for any help. I have a planned trip in two days and no way to get to a shop before hand. Can't wait to try out me new bike!!! Thanks!


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## gmcttr (Oct 7, 2006)

No problem...use a stiff putty knife or a flat blade screwdriver to pry the pads all the way back into the caliper, replace the wheel and pull the brake lever a few times to re-set the pads.

Be careful not to gouge the pads.


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## heidenspass (Mar 24, 2010)

great! I managed to get the tyre back on. thats progress, but the pads are still rubbing badly, so that the tyre barely spins.?? thank you for your help thus far. I'm seeing some light!!!


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## gmcttr (Oct 7, 2006)

You have to pry the pads/pistons farther back into the caliper. Then they can re-set to the correct gap.

If they are rubbing after that, the caliper position probably needs adjusted.


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## gmcttr (Oct 7, 2006)

http://issuu.com/sram/docs/avidbrake_setupb


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## jrabikerepair (Dec 29, 2009)

My hayes strokers did the same thing... It could be a stuck/sluggish piston.
Good solution is to remove the pads, and press the pistons out a LITTLE BIT (by pulling the levers 1-3 times). Then take a q-tip and soak it with DOT 5.1 fluid. Using the saturated q-tip, apply brake fluid to the pistons themselves, then reset the pistons using a 9mm box end wrench. Wipe away excess brake fluid with a rag and some rubbing alcohol.
Doing this lubricates the pistons and allows them to move more freely.

This advice was given to me by Hayes Tech Support, and it works very well.

Make sure that the pistons did not come out too much... Air enters the system and you must re-bleed the brakes (DOT 5.1). You can tell if this has happened by squeezing the levers (pads installed) against a rotor or spacing block. If the pads contact the rotor, and your lever is squishy, bleed the system while squeezing and releasing the bottle until no bubbles come up to the bottle.

If still no luck, try avid tech support. It is on the sram website.

Edit: make sure your caliper is centered to the rotor, this causes rubbing issues as well.


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## heidenspass (Mar 24, 2010)

yes, I've done that and it is working much more nicely!!. minor rubbing but nothing too terrible. thanks for all your help!!! now I'll try to adjust the caliper position. wish me luck mate.

next on my list, a really good how to fix your bike book, i think i could get addicted.


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## jrabikerepair (Dec 29, 2009)

heidenspass said:


> next on my list, a really good how to fix your bike book, i think i could get addicted.


My Barnett's Manual is by far the best, however, the classes make it more useful than anything, and it's definitely overkill 

I would recommend:

Park's Big Blue Book of Bicycle Repair

Zinn and the Art of Mountain Bike Maintenance

Bicycling Magazine's Complete Guide to Bicycle Maintenance and Repair: For Road and Mountain Bikes


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## heidenspass (Mar 24, 2010)

thanks for your thoroughness jrabikerepair! I'll try this.


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## heidenspass (Mar 24, 2010)

you all have been very helpful. thank you very much!


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