chrisgt: I can also suggest you think about re-packing the joints altogether...

it's pretty involved - removal of the axles, repacking, replacement of the joint cans and grease, etc. I just did this last year. These parts are still available.

Though mine had not yet started producing any unwelcome sounds(!), my boots had torn open, with grease spinning out...

I also took the advice to swap the axles L to R. This seems a sensible way to effectively double the life. FWIW, my car got over 400k miles on it before I did this job... Also replaced diff seals and many other bushings, etc. while it was all apart. Big job.

Good luck!

__________________
'83 300 SD
'05 E320 4Matic
'06 BMW 530 xi
'68 Triumph TR 250 - The only car I ever loved more than the Mercedes; who needs electricity, anyway? - Damn, why did I sell it?!
'59 Jaguar 3.4 'Le Chat Noir' - Damn, why did I sell it?!

It's difficult to make predictions, especially about the future.
- Niels Bohr