brake lever will not return
Some things to check and I'm assuming you're running V-brakes:


My first guess is that the brake cable inside the brake cable housing is sticking. Some light oil on the cable could help. (WD40 is a solvent, do not use it on cabling or chains and do not use it where you want to maintain lubrication on parts. Look for some light oil like TriFlow, or whatever your LBS sells.) If the brake cable does not travel smoothly, I would suggest a new brake cable.
If you unhook the brake cable at the front brake arms, the arms should travel smoothly and you should feel some spring action that will resist squeezing. If the brake arms have no spring to them, that's a problem.
With the brake cable unhooked, the brake hand lever should move freely. If it doesn't then oil it. Light oil should penetrate any rust, and that might take 20 minutes of sitting before it works in.


Keeping the brakes in good condition is worthwhile and important. If you don't feel confident about how they feel, seek some help. Having a front wheel misbehave can be quite dangerous. Best of luck!