Tuga,
Here is a link to a thread by Richard and Rhonda that discusses why these valves leak and how to fix them without the cost of replacing the entire solenoid and valve operator. It makes a lot of sense. Maybe you would want to use his suggestions and repair the valve seats you remove and have them ready as spares for the next leak.
http://newellclassic.com/forum/showt...ght=valve+seat
Russ