Hello everyone I am trying to replace either the o-rings or the whole push pull assembly...however I can't get the assembly out of the pvc valve. I have removed the screws on top of the assembly and the screws attaching it to the pvc valve..I don't know how much force to apply to pull assembly out. I would appreciate any ideas on how to get this thing out...I'm assuming it is something to do with the large o-rings being old. The pushpull backwash valve is old Pentair attached to Triton sand filter. Pool built in 1987, it is an inground plaster pool.