Popped rivets is good evidence that the axles are worn. Another is they are 27 years old. They are not difficult to replace. As to the plumbing you may consider replacing the copper with pex. Lot's of guidence thru the different Search categories. If you can't find an answer.....ask. Someone here will have done what you need to know about. Welcome.
Oh, post pictures. WE LOVE pictures.
Neil and Lynn.
Neil and Lynn Holman
Kirk Creek, Big Sur, Ca. coast.
1966 Trade Wind
1971 Buick Centurion convertible
1969 Oldsmobile Ninety Eight