I have a banging sound when I turn the steering.

If the banging occurs while standing still, suspect binding upper strut mounts. Reach over the top of the tire and hold your fingertips loosely on the coil spring, then have a helper slowly turn the steering wheel. If the mount is binding, you'll feel the spring wind up, then snap free and rotate when the tension gets high enough.

A steering wheel wobble at low speeds could be due to a bent wheel or warped brake rotor but more commonly is caused by a broken belt in a tire.