Peggy et. al.- A few threads back I posted about our head showing signs of aging, and asked about rebuilding or replacing. Several replies later, I was convinced that a $99 replacement was better than a $40 service kit. Last weekend I returned the service kit and bought the whole unit. Went down to the boat and replaced the old one in about 15 minutes. Four bolts and half dozen hose clamps. It couldn't have been easier. I now REALLY know what you mean when you suggest that maintenance on a clean dry system is much easier (and pleasant) than repairing a clogged and broken unit. To anyone skimming this forum- its good advice- take it! Thanks for all the help. p.s and I took the old one apart to look for signs of aging. The joker valve was distorted, and the pump plunger was losing its grip on the cylinder walls. No mineral build up in any hoses, though.