In the 4 inch tube, there's what appears to be a stainless steel sleeve. Then there is what looks like a plastic sleeve inside the stainless one. When the bolt that the plate (diverter) is attached to moves, the plastic sleeve moves inside of the stainless sleeve. My guess is the plastic piece is worn, allowing water to spurt out. If you remove disassemble the pipe/diverter you'll see what I mean. It looks like the parts are replaceable but prolly gotta get the parts from Imco.