Chassis grease...

[Rawze]

I flush mine until I see fresh, clean grease come out of them.-- always have done it this way, never had an issue... but that is just me. Guess everyone is a bit different.lol -- Most important thing is never let things run dry or get crudded up with old dry grease. Grease does separate too if left in something too long (few years) without a flush.

Depends on the components and mfgr I think. I know some tie-rod makers say not to grease past the point of the soft protective boots swelling up... but most u-joints I have seen say to flush them until you see fresh clean grease flowing out from all 4 sides, otherwise something is wrong.

There are a couple manufacturers that say not to blow out rubber grease-boots, and some that say to always flush old grease.