My pump went of the fritz around 145k miles. I bought a rebuild kit from the dealer ($106.50) (waaay cheaper anywhere else!...like around $55-$65) It took me some time to get to the darn thing, but the rest was pretty easy, and has since worked fine. Well, at least it did for another 42k miles, since then a few interesting things have happened, and I am going to rebuild the motor, with the exception of the pump.
03/83 300D 184k
07/73 280 160k