Any suggestions???? The pnuematic pinch valve on my schwing 39m gives me rock jams in the reducer if I stop pumping for more than a couple minutes. I know its caused by the cream leaking past the bladder. When inflated it leaves a 3/4 inch opening. I was just wondering if anyone else has this prob or knows of a fix. Right now I just run a little bit every couple of minutes thru the break to drop the rocks out before it plugs.

 i have the same trouble here in england where our concrete supply is very poor if i leave the rubber squeezed up for to long the concrete bleeds causing a blockedge i turn on pump without reves so bag opens let some concrete fall then turn of pump to squeeze again that all i can say my squeeze valve is a putzmeister valve that fits over the rubber

what type valve are you using, how much air pressure, is it automatic or manual, steel or fabric 4" or 3" tip hose

Are you reading your replies....? If so please respond. I can help.