Stumped by a v brake

[GlenBen]

Ive had a problem for a while now with my rear v brake. When the lever is pulled its fine. However, when i release the lever, the cable doesnt go tight again, it just hangs there all limp. It does release enough that the brake doesnt rub though.

Heres what i have tried already.

Removing the brake arms, regreasing and replacing.

Recabling, inner and outer.

Switching the cable to the opposite lever

Replacing the noodle and rubber bit.

Greasing the cables (pre and post changing)


Any thoughts? Ive done everything i can think of except changing the actual brakes, but the springs feel fine and pop straight back when pushed by hand.

 

[Milkfloat]

Spring in the lever?

He switched the lever.

Everything has been swapped out - so unless he really screwed up the recabling, it must be on the brakes themselves. Are you sure they are springing open as well as the fronts?

 

[Cubist]

Cable routing?

 

[lpretro1]

It might sound daft but we have had this loads of times - check that the brake bokcs have not developed a little lip on them - this happens when they are just aligned with lower edge just slightly under the lip of the rim. After a time as the 'lip' gets deeper they start to cause the block to stick on when the lever is released - just like the cable sticking symptom. If there is plenty of brake block you can cut the 'lip' away and realign the pad - if pads are worn change them and align so they run square on to the rim

 

[palinurus]

Have you tried adjusting the return spring tension by sticking the pin on the back of the V-brake levers in the uppermost hole on the frame mount?

 

[Vantage]

Make sure the bolt isn't pressing against the cantilever arm rather than the bearing sleeve. Some bolts have a 'countersunk' profile that can do this. Also make sure your cable run doesn't have too tight a turn around the seat tube/head tube and so on.

 

[Milkfloat]

Did he?

Yes.

 

[simongt]

You've probably done this but did you actually disassemble & thoroughly cleaned out the mech of each brake arm before regreasing - ? This sticking has happened to me and I cured it by doing the above. It's surprising how much crap gets into the mech, especially the rear pair.

 

[Milkfloat]

Where? I have read it several times and cannot see it.

Switching the cable to the opposite lever

This. Well that is how I read it.

 

[simon.r]

Have you tried adjusting the return spring tension by sticking the pin on the back of the V-brake levers in the uppermost hole on the frame mount?

Or as a quick bodge, just bending the spring that keeps the block away from the rim.

 

[I like Skol]

Or as a quick bodge, just bending the spring that keeps the block away from the rim.

Don't bodge! When fitting the brake arms to the bike have you fitted the spring pin into the middle or top hole in the frame boss? This can make a huge difference to the force exerted by the return spring. If the lowest hole is used then the arm is often almost at rest as soon as it has left the rim.

 

[Ajax Bay]

I take it the brake cable runs along the top tube. Have you got anything strapped to the top tube?
Leaving the cable otherwise in situ, remove the nipple from the brake lever and undo the securing bolt at the V-brake. Now pull the cable through both ways. Is there any resistance, either way? Why?
As @I like Skol says, to increase the spring effect at the V-brakes, undo the pivot bolt and use the top hole for the spring end. The rider relies on these springs to move the blocks away from the rims when the brake lever is released.

 

[GlenBen]

Thanks for all the answers.

I dont think its the cable routing, its not changed at all and it did work fine until recently. Not a lip on the pad either, though I have had that before also.

The spring is in the middle hole. I guess Ill try cleaning it all out again and move the spring to the top hole.

You've probably done this but did you actually disassemble & thoroughly cleaned out the mech of each brake arm before regreasing - ? This sticking has happened to me and I cured it by doing the above. It's surprising how much crap gets into the mech, especially the rear pair.

All i did was clean the hole of the arm that slides onto the frame and the grease the arm before replacing. Do you mean taking the whole thing apart to clean?

 

[GlenBen]

No, nothing on the top tube, the cable runs freely along the whole length.

 

[lpretro1]

Time for new brake mechs then?