[Vwdiesel] What's this part on my '84 Quantum TD?

[Andrew Buc]

I'm referring to the thing in the photo that looks like a large safety 
pin with a black plastic fitting on it:

http://www.flickr.com/photos/12119356@N00/

It has a sort of socket at each end that mates with a ball on a 
linkage. On the black plastic fitting to the right, the socket faces 
down. On the fitting to the left (which you can't see in the photo), 
the socket faces up. Yesterday, I think I knocked the part (while 
unscrewing the oil filter) and tore the socket to the left off the ball 
it mates with. I popped it back on, but it doesn't look too good.

What does the mechanism of which this clip (for lack of a better word) 
is a part do? Is the socket likely to break entirely in normal 
operation of the car? So far it hasn't, but I've driven the car only a 
short distance. How bad would the consequences be if it did? In any 
event, I want to replace the clip. Can anyone give me a name and VW 
part number for it? Thanks in advance.