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Old 05-21-06, 08:48 AM   #1
speed47
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V brake problem

The rear v brake on my bike does not release properly. The side where the cable housing sits does not retract from the rim. The side where the inner cable attaches works properly. If I remove the cable housing from the arm there is plenty of spring tension there and it fully retracts. I have greased the mounting point on the braze on. I have tried adjusting the tension with the adjustment screw but it does not solve the problem. I am thinking that I can probably change the position of the spring on the braze on to a hole that will provide more tension on the not working side and to a hole that will provide less tension on the working side. Is this ok? Can anyone offer another suggestion as to what to try?

thanks
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Old 05-21-06, 08:51 AM   #2
FarHorizon
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Hi Speed47!

You've tried all the things I'd have tried. I would go ahead and change the tension spring to the alternate holes as you suggest. Other than that, you'd just have to keep adding spring tension on the side that isn't retracting and keep slackening tension on the opposite side.

Let us know what worked...
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Old 05-21-06, 09:12 AM   #3
mactheknife68
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If I understand yer description, when the cable is released and the brake arms are freed there is adequate tension to allow both arms to move freely? If so there's likely friction in the cable housing. With the brakes open, pull the cable housing sections from their stops and clean them of any grit and relube them before reinstalling. If you feel some improvement then you may want to replace the cable and housing at some point for a fresh start.
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Old 05-21-06, 09:32 AM   #4
cascade168
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V brakes would appear to be straightforward, but adjusting them is not. If one boss or the other is a bit sticky this will affect performance. Remove the caliper arms, clean and lube the bosses. Make sure they are perfectly smooth (no burrs!) while you have the arms off. Blue Loctite 242 on the holding bolts when you re-install the arms. Spring tension on both sides must be very close for the adjustment screws to work correctly. Sometimes you have to bend one a bit to strengthen it (compared to it's mate). The adjustment screws should always be adjusted both sides at the same time - loosen one side and tighten the other. If things seem all out of whack, set both screws at a middle position (blue loctite on these guys, too). The side of the brake that moves the most when squeezing the hand control should be loosenned (turn adj screw out) and the other side should be tightenned (turn screw in). Loosenning the adjustment screw reduces spring tension on that side and if one arm is moving more than the other, it has too much spring tension and the way you fix that is by reducing it (turn screw out) - and then go to the other side and increase spring tension by turning the adj screw in (the same amount as you turned the other one out). If your bosses are lubed and the springs are close to the same tension, you will know when you make the correct adjustments because you will see both the left and right arm move (at the same time) to the needed side. Sometimes it will take several sets of adjustments to get both arms to move at once. Once you see them both move at once, you are very close to the correct adjustments. If you get an over correction, go back the other way and use smaller adjustments. It's correct when both arms are at the same angle away from the fork (or seat stays) and they both move the same amount to make the pads contact the rim.

This all assumes that the cable is working properly. Good luck!
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Old 05-21-06, 12:35 PM   #5
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Quote:
Originally Posted by speed47
The rear v brake on my bike does not release properly.
What kind of brake is it? Actually, to be a V brake it has to be Shimano, kind of like Kleenex.

The reason that I ask is because the answer to your question is brand specific. If it's a ProMax brake, for example, the best answer is to throw it away and get a genuine Shimano brake.
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Old 05-22-06, 08:47 PM   #6
Michel Gagnon
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Quote:
Originally Posted by speed47
The rear v brake on my bike does not release properly. The side where the cable housing sits does not retract from the rim. The side where the inner cable attaches works properly. If I remove the cable housing from the arm there is plenty of spring tension there and it fully retracts. I have greased the mounting point on the braze on. I have tried adjusting the tension with the adjustment screw but it does not solve the problem. I am thinking that I can probably change the position of the spring on the braze on to a hole that will provide more tension on the not working side and to a hole that will provide less tension on the working side. Is this ok? Can anyone offer another suggestion as to what to try?

thanks

A few options:

1. Does the brake retract all the way to the other side ?
I.E. One arm opens more than usual.

If so, I think you need to adjust both adjustment screws. There is one on each arm and both need to have approximately the same tension. If the tension is too weak on both sides, you'll get unpredictable results.

Greasing the pivots is something I need to do once a year, but it seems you have already done that. But have you inserted both springs in the centre hole? If not, that's a sure way to get uneven tension.

Cable or noodle hits somewhere. Especially if you changed something in the cable run, make sure that your cable housing or noodle doesn't hit one of the stays holding your rear rack (been there, done that), a taillight, your leg... Occasionaly, a too tight cable run might interfere with brake activation.


2. Does the brake hit in one point only?

Check that the wheel is true.


3. Does the brake take a very long time to open by itself, yet the exposed cable seems tight all the time?

Check for kinked cable or housing near the noodle.


4. Does the brake take a very long time to open by itself, and is the exposed cable on the top tube very slack at that time?

Unless you sit on the cable, that usually happens because of a kinked cable or housing along the handlebar.
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Old 05-26-06, 02:16 AM   #7
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V-brakes are easy. I just grab the springs and bend them away from the wheel to increase tension, or toward it to ease tension. When they move at the same time and hit the rim in unison, I call it good and hop on.
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Old 05-26-06, 03:36 AM   #8
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Outer cable length can be a factor sometimes, try removing the spring, putting it back together with the cable in place and moving the arm by hand.
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