My pressure-side sweep (Pentair Legend I believe) stopped working so I have been working through the possible issues. I have cleaned the filter, replaced the wheels to make sure the drive shaft is catching the teeth, cleaned out all the baskets. When I turn the cleaner on it gets good pressure for a few seconds. I can tell by lifting the sweep out of the pool and the rear jets and the tail spray across the whole yard. The wheels spin with decent force and it moves on the bottom of the pool. After a few seconds the pressure seems to drop and the jets just start to trickle out and barely shoot a couple feet. the wheels spin very weakly and it doesn't move at all. What might be going on?