I have a iphone 3G 16GB over a year old which the vibrator mortar is hitting the metal plate behind the screen whenever I push down on the right corner of the screen and turn on vibrator switch. The mortar hits something making a noise "clack clack clack." If I apply slightly more pressure on the screen, it won't work. If the vibrator switch is activated without any pressure on the screen, it will function perfectly.

everything works fine except for the vibrator hitting.

Does anyone have same experience or tips?