If your panel is cracked, I would replace it. It is like having a bear wire without insulation. You are opening yourself up to risk of shock or fire.
If your system is connected to the grid, it can generate 600V!
It will definately generate power, the glass is just to provide a hermetic seal from the elements, and has little to do with power generation, It will definately fail over time as water gets in there and rusts up the connections.