Frank,

Yes, the distribution unit that you mentioned does seem a little frail.  
Mine did exactly the same as yours and broke off at the heater 
connection.

The thing was a real pig to change also. Those one of a kind pipe clamps 
would not move easily.  Ended up breaking some of the other junctions 
off the unit in order to remove the pipes from the unit itself!

You made a good point to KEEP AN EYE ON THIS PUPPY, it would leave the 
car in a dire hole if it were out in the middle of no where!!!!

Sincerely,

Chris Gibbs
88 Westie