An observation. What you are calling "1/2 inch grey pvc" is more than likely a product called Quest. If so, my advice is to forget about trying to repair or use it and just replumb the trailer with PEX. I seem to recall that around the time the trailer was built, Fleetwood used to run some of its water pipes along the bottom edge of inside walls, covered with a plastic molding.
Happy Camping! ///// Richard D.
2006 4x4 Ford 250 SD / 2007 Flagstaff 827 FLS
One very patient wife and one furry child who travels with us. Forty-two years of trailering and camping, and I still have a blast.