Almost all mobile homes had PB pipe back then. Some had aluminum crimp rings, some had copper. The aluminum was by far the worst. Some had plastic fittings and some had copper and brass. The plastic was by far the worst. Those that had plastic fittings and aluminum crimp rings didn't stand a chance.
A failed aluminum ring would fracture right at the crimp where the hump was. It looked like aluminum that had been bent back and forth too many times. Usually the pipe would not come off, but it would spray water about as far as there was no obstruction. Sometimes there was no fracture, just a tiny stream of water coming out about the size of a hair.
The plastic fittings would just crack. T fittings seemed to be the worst. I also worked on a lot of plumbing right after a different plumber was called out. There were a surprising number of residential plumbers who did not know enough to say that they did not work on mobile homes or PB pipe. We would come out and see a splint made with a copper fitting and 2 automotive clamps.
The story is that the polybutylene would leech out platisizers because of prolonged contact with chlorine and/or other minerals in the water. This would cause cracks in the pipe that would end up being that tiny stream of water leaking and make fittings brittle and they would fail because of the movement due to the lack of clamps securing the pipe from vibration and surges.
In the late 80's and early 90's, we would fix PB with new PB, copper rings and copper/brass fittings. I started doing mobile home repair in Fresno in 1986. Total replumbs were cpvc or copper. PEx was some new space age stuff that was not in wide use yet. Knowing that the PB was crap, we were not quick to jump on a new kind of plastic pipe. Sure wish we had.
So there is a "nutshell" of my experience with polybutylene.
Today is PERFECT!
All information and advice given is for entertainment and informational purposes only. The person doing the work is solely responsible to insure that their work complies with their local building code and OSHA safety regulations.