I recently did my monovalve and it sprung apart on me too, before I could check the position of all the washers - doh! Next time (which their hopefully won't be) I'll be more careful. Anyways after looking it over the only way I could see for putting it back together was large diameter washer on top - this matches exactly the circumference of the sleeve around the solenoid coil and would seem to prevent it from slipping once installed, then wavy washer and then the other one. I check the operation of the solenoid before reinstalling by hooking it directly up to the battery.

-Colin

BTW got mine from ************** for $50.