My mountain bike has a disc brake problem......... when I sqeeze my front disc brake,it locks my front wheel... though I stop the brake ,it still locks the wheel temporarily........ please help me solving this problem

3 possible issues:

1) the cable is not moving through the housing freely. There could be a burr, a bend, a worn end or just simply rust in the housing and that is binding the cable up, not allowing for the return spring to happen and essentailly stick closed. Rock and Roll cable magic lube is the a great solution for the sticking cable. If it is bent or the end is worn then you need to replace.

2) The springs on the actual brake are binding. There should be an adjustment knob on the brakes to adjust the tension. If this does not work, then check the cable binding again.

3) The pads and/ or springs have some sort of problem. You can remove the pads and springs, clean and replace and see if the pads themselves are just sticking.

If none of these solutions work then you will need to go into a bike shop and have the mechanic look at it. You may have a broken part somewhere in the brake or lever or both.

Good luck, my guess is it is just sticking and cleaning the pads and lubing the cable will get it to stop sticking. By the way any bicycle lube will work down the cable, the Rock and Roll is just a special cable lube for sticky situations.