went to use my wf trolley the day and couldn't get any water to come out ,the pump was at full wack 99 sureflo pump , took the hoses of and snapped the little right angled thing that the hose goes onto but managed to get another of another window cleaner , with a bit af blowing the hoses we managed to get it going again , but happened again , i wiggled the hose and away it went . but i think it will do it again help any suggestion what could be causing it ,an air blockage ?????