My '95 Outback has developed a rattling noise at the front of the AC compressor. My suspicion is the compressor clutch. I cannot complain as I've got 327K on the car and it is the original compressor. I was having some issues with the AC compressor cycling on and off but all that was was an overcharged system. I bought a manifold gauge set from Harbor Freight and checked the pressures. Does anyone sell just a clutch replacement for the compressor. Everything else is working fine except that sometimes the compressor won't engage when the AC button is pushed on the dash. It always seems to engage when the defroster button is pushed though. Any thoughts?

Rattling could be the bearing in the idler pulley for the AC belt.