I have a Jabsco manual head on my h356. It has a flange at the bottom of the pump assembly that makes a right angle trun and reduces in diameter. I've taken this apart now at least one more time than I ever want to take it a part again. Finally, three of the six plastic posts that receive the machine screws on the top of the pump snapped off this past weekend. It's only a year old, but I need a new head. What do you recommend. Thanks.