V-Brake Stuck

[dhd.evans]

My v-brake on the front wheel has been giving me some bother recently; pulling on the brake causes it to close but lock in. I sensed a sticky mechanism so cleaned it out with a toothbrush then blasted it with GT-85.

Last night's ride i noticed it locked completely - managed to unfudge it with brute force and took a look at the thing last night. Both arms are sticky as hell and almost completely seized, i've removed the bolt from one lever to get a look in but that made no difference.

Anyone have any ideas about solving this issue without having to traipse to LBS?

 

[grumpyoldgit]

Which caliper is it?Probably crud in the pivot.I would strip ,clean,grease & re assemble,about an hour for a first timer.

 

[wiggydiggy]

They might have just worn out.

I was surprised when my LBS put this to me after I went though much the same motions as you cleaning/lubing the mechanism for an age, I thought you could just keep changing pads and they would last forever(ish) but apparently springs etc just wear out.

I got these Deore type as replacement for my Acera, not sure if its what you need but I'm happy so far:

http://www.chainreactioncycles.com/Models.aspx?ModelID=39004

 

[Amanda P]

Some V-brakes are very prone to this. Especially in winter, they get liberally showered with salty water and crud, and the pivot corrodes.

The cure is to undo the pivot screw and pull the brake arm off the pivot that's welded or brazed onto the frame. Clean out the inside of where the arm swivels on the pivot. If it doesn't have its own bearing, it'll probably be brass in there; pull a bit of oily rag through a few times.

Then clean up the pivot on the frame. That'll be where the real corrosion is. A light polishing with metal polish may do it, or perhaps some emery cloth if it's steel and really rusty. You need it clean and smooth.

While you have it all in bits take a look at the springs. They can rust too, so that they don't move over their stops and that makes brakes sticky. The same polishing treatment near the straight end may be necessary.

Reassemble with plenty of grease (in the pivot, not on the pad of course). Hopefully they should work and not stick. But you'll be doing it all again this time next year, if not before.

(Oh, the other thing that can make V brakes stick is that sometimes the pads wear with a step in them. As the pad wears and has to travel further along its arc to meet the rim, the longer arc takes the pad lower relative to the rim so that its lower edge isn't contacting the rim, but waving about in fresh air beneath it. That's OK -the brakes still work, but the bit waving about in fresh air doesn't wear, while the rest of the pad does, so a step wears in the pad.

Then when you brake, the step gets caught under the edge of the rim and prevents the pad moving away again when you let go of the levers. The cure is new pads, or, if there's plenty of life left in them, file the faces of the pads smooth again. Then keep them adjusted as they wear so that the whole face of the pad contacts the rim).

 

[dhd.evans]

I'd feared the brute force approach would be necessary - it's wedged on pretty tight, even with the bolt out! I took a cursory look last night and found that the trouble getting it off was getting decent leverage. Will sort that out with a Phillips flathead and some elbow grease.

I'll report back on the progress; thanks all!

 

[Shut Up Legs]

I had similar behaviour from the previous brakes on my Vivente tourer that I use for commuting, and also had trouble adjusting the pads because I found that the bolts holding the front/rear brakes to the frame were moving, because they'd both worn out. Not surprising, since I'd done roughly 40-45,000km on the bike by then. So yes, brakes last a long time, but not forever. The bolts on yours may still be OK and you can just do what Uncle Phil recommended.

 

[Davidc]

Uncle Phil's post is excellent.

Also check the cable. A frayed cable inside the outer sheath can do this. A failed outer sheath can also do it.

 

[dhd.evans]

Grime and muck were the culprits. Absolutely full of grit and muck. Soaked them in boiling water then cleaned off with a decent amount of GT85 and elbowgrease.

Hopefully will be fine for the ride home tonight.

 

[grumpyoldgit]

Well done,good result.

 

[dhd.evans]

The spring is still sticking on them so more fine tuning to be had (*sigh*) but definitely freed them up.

 

[fossyant]

You sure it's not catching on the rim or tyre ? Adjust the pads.

 

[mcshroom]

Try moving the pin on the back of the main springs to the inner of the three holes on the mount. This adds more leverage to the brakes springing back.

Also check your cable runs to see if it's the cable getting stuck. I had a problem with brakes not springing back on my commuter recently which I couldn't work out, then I realised the work stand was clamping the cable slightly and stopping it from releasing.

 

[roadrash]

uncle phils advice above , plus check inner and outer cables move free and are not sticking.

 

[Dave Davenport]

You sure it's not catching on the rim or tyre ? Adjust the pads.

That's the most likely cause, pads set a touch low and have worn a lip that catches on the rim.