Jim,
Congratulations finding the problem.
Exactly what was the issue?
Were the U-joints themselves failing?
How were they loose? In the needle bearings?
Were the U-joints tight on the splines?
If not were the splines damaged? (Both internal and external?)
Are all four of the ‘safety pins’ still good?
What was the condition of the rubber ‘doughnut’?
Were the attachments tight and lock-tabs in place?
Was the ‘flange’ on the steering rack tight on the splined shaft?
Dave @ TRE’s adventure:
Clunk in steering? Here is a possibility
What other prior work was done involving the U-joints?
When the U-joints were ‘tightened’, was anything else noticed?
Has there ever been an accident involving the front suspension or steering?
These U-joints are VERY robust.
I don’t think I have ever seen one fail on it’s own.
This is such a critical system in a 911, every detail needs considering.
Best,
Grady