cma...
I don't think it is hard to fix... just may be a good nuisance to you!
Look around the ground and make absolutely sure you did not leave a spring on the ground... sometimes these or another part pop out when VB disturbed. Do you have a name brand on the unit.. Arrow head? Mansfiled? What have you..?
Otherwise, may need to go to where the unit was purchased and buy another unit and swap out the vacuum breakers... ;)
Here is a website (click on link) that has repair parts for frost free sillcocks:
http://search.aol.com/aol/imageDetai...cuum%2Bbreaker
Parts are specific to each manufacturer... but check to be sure this is not your manufacturer... depending on manufacturer, may also be able to purchase just a
sillcock service kit (includes VB repair kit). That would require you to go where valve was purchased and ask about the VB repair kit.
Bring them a printed version of the repair kit from the website link... that way they can't tell you doesn't exist... ;)
Let me know what you think... MARK
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