Should lost CV gaiter grease be replaced?

Question

I discovered a small hole, possibly a puncture, in an outer CV gaiter on the front. The hole was right next to/under the (outer) metal ring holding the CV gaiter, so it wasn't in a very flexible bit. There was quite a lot of oily grease splattered on the inside of the wheel (and presumably much of it also went onto the road). The hole was then closed using silicone sealant.

What I would like to know is if the grease that was blown out of the CV gaiter still had a function, or whether grease that has reached the CV gaiter's "wall" is not useful anyway, because it doesn't go anywhere normally. Should the missing grease be replaced?

NB: Given the position of the hole, and the fact that the grease was pushing out, I'm fairly sure that nothing went into the CV gaiter.

The car is a 2001 Saab 9-3 (first generation; B205R)

Answer 1

Yes you need to replace the grease when you replace the boot. That grease lubricates the joint, if you don't have enough inside the boot the joint can fail prematurely. On a side note don't use one of the quick boots (the ones designed to be put on without taking the CV joint off of the car), in my experience they are worthless.

Here is an example of a boot kit, this one is $15.99 and fits a Dodge Neon

This is the split boot type that I don't recommend.

As R.. Suggested the whole CV joint for your car might be only $60 and that's certainly something to consider, it's only about 15 minutes less work to replace the whole shaft than just the boot.

Here is an exploded view of the outer CV joint. It's best to disassmeble when cleaning the old grease and dirt out.

Answer 2

Remove the shaft, and throw the boot away. Clean out the old dirty grease, after cleaning the part of course, and replace both the grease and boot. This gives you a chance to inspect the joint, and clean up any dirt residue that will speed up the deterioration of the CV joint.

Answer 3

Honestly unless you enjoy making more work for yourself, I would just seal up the hole, possibly adding grease before doing so if it's not too difficult and you can do so without making the hole worse. Taking off and reattaching the axle is a big enough job by itself, without cleaning, re-greasing, re-fitting, and putting a new boot on the CV joint, that most people would just replace the whole axle when it needs done. (For most vehicles it's a $60-120 part.) But you might as well wait until it really needs it.