I have the c v axles off and am about to replace them. The bearings in the wheel hubs turn freely and have no discernible play. But as long as I have it apart to this point, I'd like to get some grease into those bearings without removing the bearing and race ,which seems to be a difficult job. Any suggestions? I have one of those things that looks like a hypodermic needle that fits on a grease gun and it seems like that might work There are some rectangular openings around the circumference of the bearing assembly when you look at it from the differential side of the hub . Does anyone know if those openings lead to the bearing? If I can't figure out a way to get some grease in there, I'll put it back together as is because it seems OK. I would like to add some grease just to be on the safe side since I have it apart to that point. Thanks.

 

are they not what we called SEALED bearings where they do not want you to add grease but replace when worn?

Once you open you have the chance of contaminating with dirt large and microscopic which will shorten life

 

I have always found that worn tires on M-Bs make a noise that sounds like a rear wheel bearing. We just went through that on my son's 2017 GLC300. The stock Pirellis stared making that noise with about 25K miles on them. The noise went away when he replaced the tires.

 

They are not serviceable, they must be replaced. It requires a special socket to accomplish.