Air Pump noise.

My 92 300 TE is making a bearing noise from the air pump. I have never pulled one of these off. Because of the price of the pump, I am going to try a pulley and clutch replacement. From the angle of the pulley, it is a little off center due to the tighness of the belt. I hope this is the extent of the problem.

Any recommendations. Is it easier to take the pump off and work on it or do it on the car?