I have located the A/C Idler Pulley. However, I could not figure out how to adjust the tension on it, it has only one arm and one bolt. I don't want to take it out w/o first knowing how to put it back.

For those who have done this, please share your experience with me. Also, do I have to drop the compressor to replace those four o rings? It seems possible that I could remove the P/S belt and gain access the back two allen screws. Have any one done this before?