Got a problem with my shut off solenoid, standard Ionics one, it seems to be sticking open, the problem is whilst filling, the cut off is not working, and the breather pipe has now started to spurt water out all over the van

, i have read about them sticking but as it seems to be welded to the frame what shall i do?? replace or repair? I really don't want my van flooding on every fill! especially as us wfp users use to much water anyway!!!!
Any advice would be appreciated!!
Newpy