Here is a link for you to review page 27-plumbing pipes. The thing that only lets the water flow in one direction is a check-value so water can not backflow. As to your issue, a clamp should be holding the plastic intake holes. I have taped new holes to the end of the bad and slowly pulled out the old while at the same time pulling in the NEW holes. Added a clamp, but that was way before 1983 HAHA. This link to a PDF should I hope be helpful, checkout page 27 and review the full PDF information before doing anything.
https://www.gulfstreamcoach.com/medi...ers-manual.pdf This link is much new and may "help some"
http://www.roadtrekchapter.org/uploa...interizing.pdf
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2021 Mercedes-Benz 3500XD, Galleria, Li3
2005 Winnebago Tour, Cummins ISL 8.9L 450HP turbocharged
2003 Forest River, Reflections, Freightliner Chassis