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My Ultegra brake caliper is sticking(7 posts)

My Ultegra brake caliper is stickingbikeridah
Sep 4, 2002 5:02 AM
The front one to be precise. When I release the brake, the caliper doesn't spring back into the open position all the way (in fact, one pad touches the rim). Is this just a lubrication issue? If so, where do I apply?
Thanks for your input!
Was it ever right?Spoke Wrench
Sep 4, 2002 5:36 AM
If it was right when the bike was new, my guess is that the caliper has gotten bumped and needs to be centered on the fork. That takes a long arm 5mm allen wrench through the hole at the back of the fork.

If it was never right, there's an itty bitty allen screw on the left side of the caliper. Tighten or loosen that screw until the arms rest equidistance from the rim.
re: Also...Mike Prince
Sep 4, 2002 5:59 AM
If what Spoke Wrench is saying doesn't fix the problem, it could be time for new cables. You didn't say how old the bike is or more specifically the cables.

Had this happen to my rear brake a while back and putting my bike in my car trunk for a weekend caused the rear cable to kink a little bit and caused the exact probem you described.

Cleaning and lubing the cable may help in the short term, but chances are you have worn through the inner liner and have metal to metal contact. Better to replace cables and get "like new" performance again if the existing cables are old.
re: Also...bikeridah
Sep 4, 2002 6:30 AM
Hmmm, I'm ruling out the cables (they are almost brand new) and centering (just had bike rebuilt). My problem is the caliper releases about 75% of fully open - I have to coax it manually to get it back to the full open position. Cable tension seems fine. I'm thinking maybe the tension spring is too slack or there is something causing resistance in the caliper itself.
re: Also...feathers mcgraw
Sep 4, 2002 7:14 AM
If the aforementioned 'itty bitty screw' isn't in far enough, there won't be enough spring tension. Sometimes in the process of centering the calipers it gets backed out too far. Screw it in so that the bottom of the screw head is even with the top of the caliper, center the brake with the mounting bolt, then use the small screw for fine tuning.
re: My Ultegra brake caliper is stickingMike Prince
Sep 4, 2002 7:40 AM
Try it without the cable attached then. You will at least be able to isolate it as a cable issue or a caliper issue that way. Other obvious things to check (not to insult intelligence):

-is the mounting bolt tight? That could cause the caliper to pivot after the cable is released
-probably not the return spring, those are pretty strong, but is it gunked up preventing the spring end from slising smoothly through the little plastic fitting at the brake arm
-does the front brake cable housing exit the bar tape with a nice curve or does it do somewhat of a "straight line' to the caliper?

Other than that, I am stumped or you may have a lever problem.
Pivot issues versus cable/housing frictionCalvin
Sep 4, 2002 8:36 AM
First, find the cause of the problem. Loosen the cable pinch bolt. Now squeeze the arms and release. If they are fine, the problem is in the housing. You may need to new housing and a cable. You can try to just lube at first.

If the arms are sticky even with no cable hooked up, you may need to adjust the pivots.

See http://www.parktool.com/repair_help/howfix_dualpivot.shtml