I just changed the 4 duckbills and while I was at it decided to replace the old bellows as its 15 yrs old. Put back together, pressed floor pedal to let some water in the bowl (water pump was not on). Turned the head breaker and water pump on and vac motor is running but not getting any vacuum. Lifted the pedal to release more water in bowl and it is full. Appears no vacuum and I can see some water around the top of the bellows. Puzzled as to why its not working.