Once upon a time I was talking to a fellow about the rear axle in his van. He told me that when he replaced the axle bearing he packed the bearing with grease before installation so it wouldn't run dry until the gear lube could get to it. He had premature failure of that bearing. He then said he was told by someone else that you cannot grease bearings that were designed to run in gear oil, such as those in an axle. This is why his bearing failed.
Questions for those who know bearing technology:
1. Is this true?
2. If yes, what is the difference between a bearing that was designed for grease vs. a bearing that was designed for gear oil?

I just can't imagine a reason that a bearing, if designed to handle X load of a van axle, failing because of having grease on it for the short period of time before the gear lube could get to it. Sure, if you packed enough grease in there the gear oil would have a difficult time getting to the bearing rollers/*****, but the grease would be lubing it just the same anyway, right?

Thanks,
Chris

 

Whoever told him that was full of baloney.

It is done all the time, and you are correct, there is no difference in bearings.

 

Did he tighten the nut and then back it off 1/4 turn? Tight bearings don't last long.

 

Isnt a 1/4 turn a little loose? I always backed them up till the Cotter key lined up with the castle nut which is less than 1/6th. I agree with the bearings are the same but to much grease may interfere with the oil working into the bearing alowing part of it to run dry. Hence the failure.

 

No cotter key on the new nuts, they have the nylon ring on the end to stop them from backing out. I had to buy a new nut because I re threaded my original with a piece of the cotter key that broke off. I think it was almost a 1/4 turn, I loosened it until it spun freely and didnt jiggle side to side.

 

bearings are one of the things I deal with at work. I think our smallest bearing is about 10" ID tho.
oil vs grease does effect life and load. Grease is generally better than oil, however, oil is usually easier maintenance. We typically grease our seals and run ISO 220 or ISO 460 oil.
There are many things that can go wrong, especially loading the bearings with grease. filled with grease and a insufficent pre-load. a bit of contamination (grass or grit). damage from improper installation (Once saw a guy drive in a 10.25" ID double roller bearing with a steel drift and no heat. That was a $1500 bearing race he chipped.)

 

I know on tractor trailers, the hubs, bearings, races are all the same. Only difference is the hubcap. And I never noticed one failing more than the other. I think the guy you speak of did something else wrong besides lubrication.

 

I don't know. The guy who had the problem was a back yard mechanic, and the guy who gave the diagnosis was a professional mechanic. Sounds a bit far out, so I thought I'd ask others.

Thanks,
Chris

 

Oil bathed bearings far out last grease packed bearings, especially in a low maintenance environment.

Just my experience.

 

Wondering if he packed them properly, or just coated them?