Harmonic balancers are mounted on the front of the engine, connected directly to the crankshaft. They are designed to absorb many of the vibrations an engine creates during normal operation. Without this dampening effect, the engine would quickly tear itself apart from the resonation of these vibrations.
Since harmonic balancers contain a good deal of rubber to absorb the vibrations, this material will wear out over time. As they begin to deteriorate, the engine vibrations can be felt increasingly inside the vehicle. If not replaced in time this could lead to serious damage on the engine's internal components.
Replacing the harmonic balancer itself is not a terribly difficult task, given the right tools are used. That being said, getting to the part to replace it can often be a tedious job requiring the removal of many components around the front of the engine.
We stock wide variety of quality harmonic balancers from these manufacturers: