Front bearing housing

[04blackcherry]

I finally took the time to disassemble one of the old bearing units from my '04 4x4. Interesting. The knuckle attach flange housing is also the outer race for the bearings. If this part goes the hole unit is junk. The design is basically unserviceable. I do believe you could put a little more grease in it thru the ABS sensor hole. I'm thinking the grease would need to be non-conductive to keep from messing with the sensor (just a guess). The stock grease was a clear green color. The replacement bearing used a green grease also.

I believe a lack of grease caused the failure of this bearing. There was no grease on the outside of the housing from being too hot. I did not clean any grease from the unit before taking the picture either. There were 2 places where there was metal gouged from the outer race. I haven't looked close enough to determine if a roller failed. My opinion is that using the knuckle flange as the outer race for the bearing is the weak link. The housing would need to be induction hardened at the race but still remain ductile enough to not break the bolt flange ears by being too hard in this area. It can be done, but it's not a piece of cake. I will try to section the housing at the race and take a hardness reading.

 

[steved]

Grease will not affect the sensor, as long as it doesn't entrain metal from a failing unit bearing in it. The sensors are magnetic and read the "pulse" off the toothed tone ring... the grease is invisible to the sensor.

I agree that the lack of grease these have is probably their biggest problem, in fact; I know of two unit bearings on a 99 2500 with almost 300k on them... we added grease to them around 85k when we did balljoints. The grease in those (and two others from another 99) was a rusty brown.

I have stated for a long time these were not serviceable because the races are part of the housing, its nice to have a picture showing that.