Bicycle Mechanics - Need help with mechical problem, Giant Sedona

Hello, I have a Giant Sedona with flatproofing that I've had for probably a year and a half now. It's worked great, until recently. The problem appears to be in the brakes. Awhile back I noticed when I squeezed the brakes sometimes they would snap back. Nothing major it seemed. Then a couple days ago I noticed that the brake pads are slammed shut on the wheel of the bicycle. When I try to ride it, the brake rubs against the wheel slowing the bike down a bit. My dad told me nothing is wrong with it, and that I should ride it to let it 'work itself out'. However my gut tells me something is wrong. Not only that, there is what appears to be marks from the brake pad around the rim of the wheel. Any advice on how to fix it? Is there a way I can ajdust the brake pads?

Appreciate any help greatly. I ride my bike to the gym and back 9 miles a day. I love the excerise and I enjoy riding it.

Thank you!
Kevin

Kevin, The marks on the rim from the brake pad can be normal wear, brake arms not returning to 'home' are not. The piviot may need lubrication or the cable(s) replaced or relubed.

Brad

Park Tool has useful info about general and specific bike adjustments.

http://www.parktool.com/blog/repair-help/linear-pull-brake-service-v-brake-type

ten to one you're problem is simple and caused by corrosion or a lack of lubrication.

As long as the corrosion isn't severe both are cured the same way, with a few drops of light oil. Start by adding a drop to the lever pivot and the brake pivots, and work it in by working the brake lever and if necessary pulling the brake arms open, for a few cycles.

Then use a bit of string to hold the calipers closed, which should give you some slack in the cable. If the brake has a tension relief mechanism open it for more slack. This should give you enough room to pull one of the housing away exposing the inner wire. Drop oil on the wire and let it wick into the housing. Sliding the housing back and forth within the available slack will help carry the oil down it's length, and add oil slowly until you feel the housing sliding smoothly.

Release the brake, being careful to guide the ends of the housing back into the ferules at each end and you should be good to go. If not a trip to the LBS may be warranted for a more detailed review and probably a cable replacement.

Is the brake rubbing on one side? "Slammed shut" to me means that the brake is pressing against the rim with both pads and the wheel won't turn. How about a picture?