Peterbilt wheel bearings

[Chris142]

My truck has oiled bearings in it. I am going to do some work on the front wheels and was thinking of packing them with grease instead of oil this time.

The truck is just a toy and does not carry any weight. It originally had greased bearings in it and someone replaced the seals and added oil hubs to it.



It sits alot and when it does it leaks some oil out, even with new seals. Leaking hub seals are a big problem if I get pulled into any open scales and inspected.

I don't think grease will leak much or maybe none even with a worn seal.

Should I use Moly grease or regular Lithium based grease? Stuff I can find at the local auto parts store should be ok?

 

[chief]

Packing them with grease will be just fine. I use Mystik Hi Temp. Pack them really good and coat the lip of the seal with grease also. Most all container chassis use grease packed bearings without problems and heaven knows they are not maintained. Just follow the recomended torque spec for the bearings.

 

[Kestas]

I personally think oil is superior to grease as a lubricant for bearings. Grease is used when it isn't practical to contain an oil system, or if rotation is slow.

But given your unique situation, I agree that changing to grease is a good idea.

 

[George7941]

FOR the OP, grease is the way to go.

I prefer oil-lubricated bearings for trucks in general because it is so easy to drain the old oil and refill with fresh oil, so you are never running with heavily contaminated lubricant.

With grease-packed bearings, it is a lot more work to replace contaminated lubricant.

 

[another Todd]

Oil lubed bearings should not leak. With the proper inner seals and properly installed hubs leaking just should not happen. You can get an occasional leak just like anything, but starting with new seals and hubs your first leak shouldn't be for hundreds of thousands of miles and/or many years of service...and you never have to repack them.

 

[alreadygone]

Another vote for Mystik HT.

Bob

 

[onion]

I've seen/done this on plenty of trailors and occasionally on trucks. Todd, when parts get old, run in rough/dirty conditions, and/or sit for long periods of time, it can be hard to keep oil-bath hubs sealed. Of course they "shouldn't" leak. But they do. And grease-packing is an easy and common fix. I've done it plenty of times and never had any problems with it.

I always use whatever multipurpose lithium grease is handy. I've read that roller bearings tend to 'skid' with moly grease, so I avoid it for those applications.

 

[Kestas]

Skidding in a roller bearing is a phenomenon that occurs under a combination of high acceleration and light loading. Automotive and truck wheel bearings don't really fit in this category.

 

[onion]

Good to know.

So in your opinion, moly grease is ok for wheel bearings?

But perhaps no so good for roller bearings in engine-driven accessories? (I'm thinking mainly of certain industrial diesel engine water pumps with hand-packed roller bearings)

 

[George7941]

I stock two greases, moly grease for chassis fittings and non-moly grease for wheel bearings, and have done so for decades. I have done it for the reason Onion mentioned above.

 

[Kestas]

I have seen many, many failed wheel bearings across many product lines. None of them have showed even a hint of skidding. Our company manufactures OEM wheel bearings and I handle the technical forensics of the warranty. I don't know where this misdirected fear of skidding in wheel bearings comes from.

Besides wheel bearings, I've examined failed bearings in many other types of applications. Skidding is a rare phenomenon. I doubt that a good mechanic could even recognize skidding in a bearing.

Onion, I wonder who is the author that wrote about skidding (if you can remember)? What was the scope of the article?

Moly grease is a good EP additive, and is recommended for automotive and wheel bearing application. Also make sure the grease is heat-resistant.

 

[Tempest]

Kestas, do you ascribe to the <3% moly content for wheel bearings?

 

[onion]

Kestas- I don't remember where I read it. It was just something I read in passing many years ago.

But your explanation makes sense, and now I won't worry about moly grease with wheel bearings.

 

[alreadygone]

"But your explanation makes sense, and now I won't worry about moly grease with wheel bearings." Onion


Onion, we'd best pay attention!!! The bearing king has spoken!

At least I'm gonna listen to K. when he offers area of expertise advice.

Bob

 

[onion]

Hey- I was deferring to our resident bearing engineer. No arguement here.