Bicycle Mechanics - V-brakes won't spring back

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4evrplan
12-14-09, 07:28 PM
They just stay clamped and feel and sound kind of gritty when I work them by hand. Because of this, the cable was loose enough that it fell off of the little braze-on cable guide holder thingy. Is the most likely culprit dirt in the springs and on the posts or in the cable guides? I figure it should be easy to take the brakes off and clean them, but how do you clean dirt out of cables guides? WD-40, or would that damage them? What do I lube them with after cleaning? I've got some of that spray on chain lube stuff, would that work? Anyway, if cleaning the brake fixes it, I probably won't mess with the cable.
bikinfool
12-14-09, 07:43 PM
Sounds like the calipers are in pretty bad shape and need a full dismantling, cleaning and lubing. You may need to replace housing and cable, maybe even the noodle, hard to tell from your description. You could start here http://www.parktool.com/repair/readhowto.asp?id=21
operator
12-14-09, 07:58 PM
They just stay clamped and feel and sound kind of gritty when I work them by hand. Because of this, the cable was loose enough that it fell off of the little braze-on cable guide holder thingy. Is the most likely culprit dirt in the springs and on the posts or in the cable guides? I figure it should be easy to take the brakes off and clean them, but how do you clean dirt out of cables guides? WD-40, or would that damage them? What do I lube them with after cleaning? I've got some of that spray on chain lube stuff, would that work? Anyway, if cleaning the brake fixes it, I probably won't mess with the cable.
Find out what's causing the brake arms to bind. Corrosion on the canti stud interface? Spring needs to be bent? Both? If they are cheap brakes like the low end shimano or worse you might be better off replacing them. Deore level brakes start at around $20.
4evrplan
12-14-09, 07:59 PM
I forgot there was a quick release to disconnect the cable from one side. I just did that and felt the action by hand. The problem is definitely with the housing and/or cable and not the brake itself. They move smoothly and silently with firm spring force when they're not being pulled by the cable. I tried to flush it out with that little straw attachment on a can of WD-40, but there's not enough clearance to wedge the tip in there between the cable and housing, so I'm probably going to have to disassemble it to clean it. That tiny bit of WD-40 on each end of the housing DID get it smooth enough to spring back though, even if the dirt didn't come out. I don't have very many miles on this bike at all, so I really hope this isn't going to be a regular problem.
They just stay clamped and feel and sound kind of gritty when I work them by hand. Because of this, the cable was loose enough that it fell off of the little braze-on cable guide holder thingy. Is the most likely culprit dirt in the springs and on the posts or in the cable guides? I figure it should be easy to take the brakes off and clean them, but how do you clean dirt out of cables guides? WD-40, or would that damage them? What do I lube them with after cleaning? I've got some of that spray on chain lube stuff, would that work? Anyway, if cleaning the brake fixes it, I probably won't mess with the cable.
Something I would like to add. A quick way to see if it is your V brake assembly is to merely squeeze the two arms together, remove the noodle attachment, and then move each arm back and forth to feel if there is any stickyness or real resistance. If so try some oil like Tri-Flo or something similiar to that and apply it in the peg of each arm. MAKE SURE you do not get any on the pads or the wheel.
4evrplan
12-14-09, 08:02 PM
Find out what's causing the brake arms to bind. Corrosion on the canti stud interface? Spring needs to be bent? Both? If they are cheap brakes like the low end shimano or worse you might be better off replacing them. Deore level brakes start at around $20.
Yeah, they're the cheap Shimano brakes, but seem to be working fine (see my post above). I probably will consider the Deore when they start to fail; $20 isn't so bad at all.
operator
12-14-09, 08:02 PM
I forgot there was a quick release to disconnect the cable from one side. I just did that and felt the action by hand. The problem is definitely with the housing and/or cable and not the brake itself. They move smoothly and silently with firm spring force when they're not being pulled by the cable. I tried to flush it out with that little straw attachment on a can of WD-40, but there's not enough clearance to wedge the tip in there between the cable and housing, so I'm probably going to have to disassemble it to clean it. That tiny bit of WD-40 on each end of the housing DID get it smooth enough to spring back though, even if the dirt didn't come out. I don't have very many miles on this bike at all, so I really hope this isn't going to be a regular problem.
You're doing it the hard way.
Remove the housing to expose the entire cable, then lube lightly the entire length and reinstall.
I forgot there was a quick release to disconnect the cable from one side. I just did that and felt the action by hand. The problem is definitely with the housing and/or cable and not the brake itself. They move smoothly and silently with firm spring force when they're not being pulled by the cable. I tried to flush it out with that little straw attachment on a can of WD-40, but there's not enough clearance to wedge the tip in there between the cable and housing, so I'm probably going to have to disassemble it to clean it. That tiny bit of WD-40 on each end of the housing DID get it smooth enough to spring back though, even if the dirt didn't come out. I don't have very many miles on this bike at all, so I really hope this isn't going to be a regular problem.
Umm ok lol. I was a little late on the response. Hope all works out. Cheers and good day.
4evrplan
12-14-09, 08:21 PM
You're doing it the hard way.
Remove the housing to expose the entire cable, then lube lightly the entire length and reinstall.
Okay. When I said "disassemble", I really meant remove the housing. I'll give it a shot, but I guess I should read the parktool link first...
sonatageek
12-15-09, 04:31 AM
If you need to replace the brakes JensonUSA has the Avid Single Digit 7 for $21.95 per set.
If you need to replace the brakes JensonUSA has the Avid Single Digit 7 for $21.95 per set.
That really is a good price, have to check their site out myself :) .
AndrewP
12-15-09, 10:31 AM
If the housing goes downwards in a U, rain can collect inside and cause rust. This is a common feature on step-through bikes. It helps to cut the housing at the lowest point and install ferrules on the ends. This allows the water to drain.
vredstein
12-15-09, 02:22 PM
If the housing goes downwards in a U, rain can collect inside and cause rust. This is a common feature on step-through bikes. It helps to cut the housing at the lowest point and install ferrules on the ends. This allows the water to drain.
Do you mean to cut a slice in the housing, through the plastic outer casing, between the steel coils, and on through the plastic liner, kinda like creating a drain hole?
Examine the cable itself. Even a little corrosion will cause a big problem. If there is any corrosion, replace the cable. If the housing is unlined, replace the housing.
Panthers007
12-15-09, 04:32 PM
When you lube the cable, be sure to use a good oil like TriFlow. The Teflon in it really helps. Just don't use grease. Grease can harden and make your problem worse - not always, but it happens.
Re: Avid SD 7's at $21.95: Excellent! I have the SD 7's myself and paid about twice that price. And would again if need be. Those are truly fantastic v-brakes.
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