Brakes won't release after being applied?

Question

My son recently received a second hand bike with both hand and pedal (?) brakes. He had been using the pedal brake because the hand brakes for both the front and rear were too loose to work well. When you would apply the they barely touched the rim.

I attempted to fix the brakes by tightening up the cable which worked... sort of. Now the issue is that the brakes won't release after they are applied. They aren't applied with the same force as when the hand lever is applied, but they are still touching the rim which makes the bike painfully slow. If I pull open the caliper itself then the wheel spins freely.

I am referring to rim brakes; the types of hand brakes where there is a separate lever for front and rear and when you squeeze them little pads touch to the rim to stop the bike.

How can I adjust the brakes in such a way that they apply pressure to the rim but also release when the lever is released?

Answer 1

Brake calipers have return springs to move open the caliper arms after closing force supplied by the force on the brake cable from the levers is removed.

If the calipers are not opening there are several things that can cause this:

• Return springs are too weak
• Caliper pivots stiff or jammed
• Brake cable friction is preventing it from retracting through the housing, either due to contamination or poor routing.

Many linear pull or V-brake calipers have return spring adjustment screws near the pivot. You could try increasing the return force and see if that sufficiently opens the calipers.

Disconnect the cable from the calipers. With the cable removed do the calipers move freely? If you close the caliper arms by hand is there a reasonable return spring force opening them?

If the calipers look OK, try cleaning and lubricating the cables as in mattnz's answer.

Answer 2

Have a look at Park Tools website for advice on how to adjust the brakes

Linear Pull or Side Pull

In your case, I suspect the problem is too much friction in the cables. Cables are considered a consumable item, and replacing them is not expensive or particularly hard. You do need proper cutters to do the job easily though – so it could be worth getting your local bike shop to do it.

Although the best option is to replace the cables (Inners and outers), you may get away with a clean and lube. Unhook the cables so the outer can slide up and down the inner easily, using a clean rag, wipe the inner clean and slide the outer up and down. When you have got as much as you can, drip a light oil over the inner and slide the outer up and down a few times and wipe clean.

Also consider putting on new brake pads – the pads harden with time and lose effectiveness meaning the braking is not as good as it should be. Although pads are relatively cheap, for a child's bike I recommend a good brand like Koolstop as children do not have the arm strength needed if the brakes are not working well.

Answer 3

Try getting new brake levers or new cables because the cables might be worn and creating more friction. or the brake levers' return springs might be weakened.