Insert pieces on Toe Rods & RUCAS

[revsx]

I recently bought a set of used Toe Rods and RUCAS from a buddy.
On the joint side of them there are little cylindrical inserts. There are two on one toe rod and 1 on each of the other toe rod and both rucas.
I was just curious what they are used for, if they are necessary (I am assuming they are), and if I could new ones from Megan still or have new ones made?
Thank You.

[archonftw]

http://zilvia.net/f/chat/297481-small-questions-thread-search-first-use-instead-making-new-threads.html

[revsx]

Didn't see that thread, sorry.