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Brake Trouble / Road Bike
Hello.
I just changed the brake cable on my old Myata Road bike..it has Shimano 105 Brakes when I apply the rear brake the one pad stays on the rim it does not spring back into place the brake levers are also 105 AERO they are not STI how can I fix this problem ? are I installing the cable wrong ? Thanks Rob Wille |
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#2
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Brake Trouble / Road Bike
"Rob" wrote in news:MZtEe.21990$%K2.7663@pd7tw1no:
Hello. I just changed the brake cable on my old Myata Road bike..it has Shimano 105 Brakes when I apply the rear brake the one pad stays on the rim it does not spring back into place the brake levers are also 105 AERO they are not STI how can I fix this problem ? are I installing the cable wrong ? Thanks Rob Wille Probably not anything to do with the cable, other then the act of installing it...The mounting bolt has likely been turned slightly, which can happen when doing brake work. You can sometimes recenter the calipers by turning the mounting nut, but be careful you're not loosening them, There may be wrench flats on the bolt by which to center it. Depending on their size, you may be able to use a cone wrench, or if the flats are smaller, Park has a special wrench for this. (http://www.parktool.com/tools/OBW_2.shtml) And be prepared to do fine- tuning. Because of the mechanics of sidepull brakes, it can look centered, but after a few applications of the brakes, it can get out of whack again, which can be frustrating. If at first you don't succeed... -HW |
#3
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Brake Trouble / Road Bike
Rob wrote:
Hello. I just changed the brake cable on my old Myata Road bike..it has Shimano 105 Brakes when I apply the rear brake the one pad stays on the rim it does not spring back into place the brake levers are also 105 AERO they are not STI how can I fix this problem ? are I installing the cable wrong ? Thanks Rob Wille The problem is your (lack of) punctuation. Or isn't you? Please answer these questions: - Did you replace the inner wire only, or did you also replace the outer (housing)? - If you installed housing, did you cut it cleanly? - Is it possible you kinked the cable? - Have you pulled the cable out to have a look? - Did you mess around with the caliper? - How does the brake caliper behave without the cable attached (squeeze it)? Please try to use punctuation it is really nice I mean people don't like reading stuff without it the right thing you are more likely to get answers don't be stubborn what am I doing? Robin (message lost in the delivery) Hubert |
#4
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Brake Trouble / Road Bike
Robin Hubert wrote:
Rob wrote: Hello. I just changed the brake cable on my old Myata Road bike..it has Shimano 105 Brakes when I apply the rear brake the one pad stays on the rim it does not spring back into place the brake levers are also 105 AERO they are not STI how can I fix this problem ? are I installing the cable wrong ? Thanks Rob Wille The problem is your (lack of) punctuation. Or isn't you? Please answer these questions: - Did you replace the inner wire only, or did you also replace the outer (housing)? - If you installed housing, did you cut it cleanly? - Is it possible you kinked the cable? - Have you pulled the cable out to have a look? - Did you mess around with the caliper? - How does the brake caliper behave without the cable attached (squeeze it)? Please try to use punctuation it is really nice I mean people don't like reading stuff without it the right thing you are more likely to get answers don't be stubborn what am I doing? Robin (message lost in the delivery) Hubert Yes, I am an ass. Robin (not afraid of the truth) Hubert |
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Brake Trouble / Road Bike
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#6
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Brake Trouble / Road Bike
Rob Wille :
I just changed the brake cable on my old Miyata Road bike... When I apply the Shimano 105 rear brake, one pad stays on the rim and does not spring back when released. The brake levers are also 105 AERO and not STI. How can I fix this problem? Am I installing the cable wrong? It's not the cable! Dual Pivot brakes were introduced to prevent the asymmetric pad movement you describe. You'll notice that the return spring slides in the caliper when the brake is used. This sliding assumes that both spring ends are perfectly lubricated, which they are not. Therefore, brake pads in single pivot, and even centerpull brakes, generally do not retract equally after use in rain or dusty terrain. Unfortunately, bicycle repair shops, unaware of the cause, use hammers and punches to bend the offending spring or repeatedly rotate the center bolt instead of cleaning the contact and giving it a drop of oil. Just a drop of oil is often enough. Hold the pad that moves readily against the rim with the thumb while pumping the brake leaver to get the other one freed up. http://www.sheldonbrown.com/brandt/brakes.html Thanks Jobst Brandt |
#7
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Brake Trouble / Road Bike
Rob Wille wrote:
I just changed the brake cable on my old Miyata Road bike... When I apply the Shimano 105 rear brake, one pad stays on the rim and does not spring back when released. The brake levers are also 105 AERO and not STI. How can I fix this problem? Am I installing the cable wrong? Jobst wrote: It's not the cable! Actually, it could be. If the loop of cable running from the back end of the top tube to the brake caliper is too short, and possibly even if it's too long, it can do this. See: http://sheldonbrown.com/cables for tips on cable installation. Dual Pivot brakes were introduced to prevent the asymmetric pad movement you describe. But he doesn't have those. You'll notice that the return spring slides in the caliper when the brake is used. This sliding assumes that both spring ends are perfectly lubricated, which they are not. Therefore, brake pads in single pivot, and even centerpull brakes, generally do not retract equally after use in rain or dusty terrain. Shimano SLR calipers use nylon or Teflon pads that the spring bumps against, which generally don't reqire wet lubrication. These are the finest single-pivot calipers ever made. I've got these on my fixed gear tandem... Unfortunately, bicycle repair shops, unaware of the cause, use hammers and punches to bend the offending spring That technique was appropriate for some older sidepulls, models dating from the early '70s and older, and was the only way to regulate the centering of the calper. or repeatedly rotate the center bolt Campagnolo invented the center bolt with wrench flats to permit it to be turned/held with a cone wrench for correct centering. This was a major breakthrough. For the Shimano single-pivot sidepulls, the end of the center-bolt is the point to turn/hold, using either a 5 mm Allen wrench or a 12 mm box wrench. Best to loosen the mounting nut, turn the center bolt to center the caliper, then tighten the mounting nut while holding the center bolt from turning. instead of cleaning the contact and giving it a drop of oil. Just a drop of oil is often enough. The oil is the way to go for calipers that have metal/metal contact between the spring and the arm. Sheldon "Symmetry" Brown +----------------------------------------------------------+ | Persecution is not an original feature in any religion; | | but it is always the strongly marked feature of all | | religions established by law. | | Take away the law-establishment, and every religion | | re-assumes its original benignity. | | Thomas Paine -- The Rights of Man, 1791 | +----------------------------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide http://captainbike.com http://sheldonbrown.com |
#8
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Brake Trouble / Road Bike
Sheldon Brown wrote:
Shimano SLR calipers use nylon or Teflon pads that the spring bumps against, which generally don't reqire wet lubrication. I used DuraAce 7402 (the last single pivot DuraAce) with those pads and they went off center when dirty... These are the finest single-pivot calipers ever made. I've got ....while my SunTour GPX single pivot with two internal springs stay centered, regardless of dirt. YMMV, mine does. -- MfG/Best regards helmut springer |
#9
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Brake Trouble / Road Bike
Sheldon Brown writes:
I just changed the brake cable on my old Miyata Road bike... When I apply the Shimano 105 rear brake, one pad stays on the rim and does not spring back when released. The brake levers are also 105 AERO and not STI. How can I fix this problem? Am I installing the cable wrong? It's not the cable! Actually, it could be. If the loop of cable running from the back end of the top tube to the brake caliper is too short, and possibly even if it's too long, it can do this. Let's assume that much about brake adjustment is understood. tension in the cable should have little effect on centering, at least to the amount that they might not move equally. See: http://sheldonbrown.com/cables for tips on cable installation. Dual Pivot brakes were introduced to prevent the asymmetric pad movement you describe. But he doesn't have those. Who said he had dual pivot brakes? I only mentioned that because this is a classic problem in single pivot brakes. You'll notice that the return spring slides in the caliper when the brake is used. This sliding assumes that both spring ends are perfectly lubricated, which they are not. Therefore, brake pads in single pivot, and even centerpull brakes, generally do not retract equally after use in rain or dusty terrain. Shimano SLR calipers use nylon or Teflon pads that the spring bumps against, which generally don't require wet lubrication. I installed Teflon sleeves in my Campagnolo brakes in the 1970's and realized that the effect was minimal. We wouldn't have dual pivot brakes today if plastic sleeves were an adequate fix for that problem. These are the finest single-pivot calipers ever made. I've got these on my fixed gear tandem... Unfortunately, bicycle repair shops, unaware of the cause, use hammers and punches to bend the offending spring That technique was appropriate for some older sidepulls, models dating from the early '70s and older, and was the only way to regulate the centering of the caliper. I don't believe it was ever appropriate. The anchor bolt on those brakes could be rotated and the springs lubricated just the same as on later more expensive brakes. It was on Universal side pull brakes that I first recognized the problem and cringed when I saw the hammer routine. or repeatedly rotate the center bolt Campagnolo invented the center bolt with wrench flats to permit it to be turned/held with a cone wrench for correct centering. This was a major breakthrough. As I said, you could rotate the center bolt without the 13mm wrench flats and I did. It was one of my disappointments with Campagnolo because since those days I designed a return spring that does not have (cosine error) slip when returning the caliper. It's coil is concentric with the center bolt and does not have this problem. For the Shimano single-pivot sidepulls, the end of the center-bolt is the point to turn/hold, using either a 5 mm Allen wrench or a 12 mm box wrench. Best to loosen the mounting nut, turn the center bolt to center the caliper, then tighten the mounting nut while holding the center bolt from turning. instead of cleaning the contact and giving it a drop of oil. Just a drop of oil is often enough. Since the spring does not change, logically only cleaning and lubrication is the right response. It has nothing to do with whether there is a solid lubricant at the spring contact. The oil is the way to go for calipers that have metal/metal contact between the spring and the arm. Sheldon "Symmetry" Brown Dual pivot brakes are not symmetrical and that's where we're at! Jobst Brandt |
#10
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Brake Trouble / Road Bike
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