78 series steering linkage

This relates to the steering linkage that connects the steering column to the steering box on 78 series cruiser utes. After about 40 000 klms the front end of my cruiser developed a knocking noise that after a process of elimination could not be found. Eventually I realized that the above mentioned steering linkage had a slight amount of play and after comparing to one on a new vehicle which had no play I decided this to be the problem. The play was not in the universal joints but in the slip yolk that allows the linkage to slide when fitting. As a temporary fix I cut a piece of poly pipe and fitted this over the mating parts of the slip yolk and pulled this up hard with cable ties. This 50 cent fix up worked so well it became a permanent fix until a recent trip over corrugated road when the knocking returned, upon inspection a slight amount of play had returned to the linkage. With over 2500 klms to travel back home I wanted it fixed so I removed the poly pipe and forced silkaflex into the slip yolk and around the mating parts before again fitting the poly pipe and cable ties. I admit this is a bit of a rough fix but it seems to have permanently solved the problem. The strange thing is nobody else I have spoken to including 4wd specialists and the local toyota dealer have come across this. Maybe my experience could help somebody else and I would be interested to know if anybody has had this problem.