Wheel Bearing Greasing - A Modern Perspective

[huntindog]

UPDATE TO MY ORIGINAL POST
First, I want to say I am happy that my post garnered so much attention and variety of opinions. That is one of the great benefits of this forum, so that all possible approaches are put on the table. For most of our trailer issues, there is rarely a single right or wrong way to do things, and each person has to choose his own path.

To those who insist that a full disassembly of each wheel is important at occasional intervals, I couldn't agree more. Certainly, at some point, I'll want to check the condition of my brake shoe linings and magnets, and, yes, maybe even the condition of the bearings (although I question whether the average shade tree mechanic would know a bad bearing from good, unless the cage had failed).

Today I finally got around to greasing my bearings. Granted, my trailer is near-new, with only about 1,500 miles logged. Those bearings should need nothing, but after reading some contributors' posts claiming they found dry bearings on almost new trailers, I decided to take the cautious approach.

I carefully followed Dexter's instructions and video... Jacked up one wheel at a time, placing my jack just under the u-bolts at the axle. It only took a couple of pumps on the jack to lift the tire a inch or so off the ground.
Then I popped off the plastic cap in the center of the hub (turn the wheel around and you'll see a little indentation in the cap where you can insert a thin screwdriver and off it comes.

Next, I used a hooked tool to catch an edge of the rubber seal just inside, removed it and set it aside. The grease nipple is visible now, just inside the hub

With grease gun attached, I started pumping grease through the hub, turning the wheel as I went to fully disperse the grease. Anyone who has ever used a grease gun before knows the difference between light pressure to flow the grease, or hard resistance where something wants to let go (like that rear seal)

I found that each hub took 14-18 full pumps of the gun before the grease started oozing out of the outer bearing. I just kept going until I had about an inch or so glob of grease exiting from the hub. At no time on any of the wheels did I detect ANY increase in back pressure while pumping which might indicate possibility of blowing out the seal. I am now absolutely convinced you could run a whole tube of grease through that hub without endangering the seal.. It is just going to keep coming out the front of the hub indefinitely (leaving a huge mess of course).

I was also encouraged to observe that, with each wheel again, when the grease started oozing out, it came out very consistently all the way around the circumference of the bearing, so I am very comfortable that each bearing got a good thorough greasing.. most likely far superior than those so-called bearing packing tools, which I've never had much use for.

One contributor to this thread claimed it took almost an entire cartridge of grease per hub? Unless he was talking about those little mini-guns with cartridges about the diameter of a nickel... honestly, if you just visualize the construct of the drum, hub, and axle, it is hard to imagine that you could pack a whole cartridge worth of grease in there. Instead, I began my job with less than a full grease cartridge, and still had grease in the gun after completing all four wheels.

Finally, I do question several contributors who say they "Give a couple of pumps with the grease gun periodically".. In my opinion, to properly grease those bearings, you most definitely do need to keep pumping until that cavity completely fills and grease exits through the outer bearing all the way around. Anything less than that, you're just p**ssing in the wind.

I suppose that if abnormal resistance is encountered while using the gun, then that might warrant removing that drum and investigating the cause.

After my first wheel, which was just behind the front steps and most difficult to get a jack in, the other wheels literally took less than 10 minutes each to grease. In fact, the most difficult task was getting that rubber outer plug back in place when done. I finally discovered the trick was to really clean out the residual grease from the hub opening, and clean the plug as well.. otherwise, that little bugger squirmed around like a greased pig!.

I hope my experience sheds further light on what I believe is a major innovation in bearing maintenance. Thank you Dexter and Lippert for bringing us into the 21st century!

The part you are missing. The dexter video shows a ring of dirty grease exiting, at which point they call it done..... That ring of used grease is from the outer bearing! The dirty inner bearing grease is still in there... Somewhere! At some point in a future greasing it will enter the outer bearing, and you will not know it. For a complete change out of the dirty grease from BOTH bearings WILL require almost an entire tube of grease for each wheel!

[Scott'n'Wendy]

UPDATE TO MY ORIGINAL POST

I hope my experience sheds further light on what I believe is a major innovation in bearing maintenance. Thank you Dexter and Lippert for bringing us into the 21st century!

You're still ignoring Dexter's recommendation to pull the hubs and inspect the bearings every year. Detecting a bearing going bad when in your hand is very easy. But, as I said before. Your trailer - do as you wish.

[CoyoteHauler]

This forum is a wealth of information and I appreciate its existence. That said, I have noticed a common trend for "contributors" who like to pass along rumors/mis-information they have read elsewhere, but have not experienced or observed themselves, and the rumors seem to perpetuate themselves.

Nothing could be more frequent than discussions about wheel bearing maintenance. I respect those who have chosen to remove all 4 wheels and drums, pry out the rear bearing seals, and repack their bearings every few thousands of miles, and who poo-poo the innovative external greasing feature of most all of the axles these days.

But I have to ask.. when was the last time you packed the bearings in your 5,000+ pound Ford truck, in spite of driving 40-50k miles per year? The basic construct of most vehicle bearings is pretty much identical to our trailers.

I almost drank the Koolaid myself regarding rash warnings about using the external grease nipples ("you will blow out the rear seal with too much pressure").

That was before I decided to look at the official company videos from both Lippert and Dexter (not just a video from some shade tree mechanic holding the "camera" in one hand.

If you look at the internal construction of these new hubs, you will see that grease flows through the center of the axle exiting BEHIND the inner bearing, then travels through the bearing along the axle up to the outer bearing, where it comes on through *under gentle grease gun pressure, and finally exists at the front of the bearing and hub.

Here is Dexter's official video describing the greasing process.. Lippert's is near-identical: https://www.youtube.com/watch?v=XT0RKDGgDm8

Yes, both companies DO suggest that you jack up (without removing wheel or drum) and turn the wheel slowly while greasing to assure complete propagation, and continue pumping your gun until you see all the old grease exiting the front and new grease pushing from behind.

So.. I submit a few points based on manufacturer's data, not baseless rumor:
1) No, 2-3 pumps of the grease gun will accomplish virtually nothing. It DOES take a good bit of grease to displace the old grease in both bearings and the internal hub housing.
2) It would be extremely unlikely to "blow" a rear seal, since there is never any significant restriction to the grease's path through both bearings before exiting the front. You could pump a gallon of grease through that bearing, and all you would get would be a huge glob of grease coming out around the outer bearing.

The thing is, systems do improve over the years, in many cases making maintenance chores easy. Just because someone has used "old-school" technigues for the past 20 years doesn't necessary validate that practice with new, improved systems.

Sure, I suppose there is some value in "inspecting" the bearings from time to time, just as you could inspect the same on your tow vehicle, or maybe even your driveshaft bearings, but most people don't, and seem to get along just fine.

For me, I'll just follow the axle manufacturer's guidance (sadly missing from any documentation provided by the trailer manufacturer), spend about 5-10 minutes per wheel, perhaps every 10,000 miles or so, and used the saved time for another margarita!

Thanks paulridge. Any information offered is great as we all add to our own knowledge base and experience of what we do for maintenance of our trailers. The important thing is, that us frequently but our trailers on the road, pay attention to our trailers and tow vehicles and try to pass this information onto folks who can use it. Thanks again for adding this information.

[JM0397]

Great thread for us newbies to get acquainted with the finer points of deep maintenance items, thank you all for the input!
After a few trips, we have about 1000 miles on our new rig. Knowing that I'll have to break down the bearings for proper inspection after the season, but wanting to ensure they are mostly properly lubed for now, I am familiar with using a grease gun and modulating the pressure.

A few of you mentioned be sure you use the proper grease, so:
What is the recommended type/weight of grease to use to top off the wheel bearings?

[Kevin2282]

The Dexter approved grease chart is on Page 53 in the attached PDF. I have used Citgo Mystik JT-6 for years with zero issues. I could not easily find JT-6 last year so I used Shell Rotella Heavy Duty Lithium Complex #2 .

[huntindog]

Great thread for us newbies to get acquainted with the finer points of deep maintenance items, thank you all for the input!
After a few trips, we have about 1000 miles on our new rig. Knowing that I'll have to break down the bearings for proper inspection after the season, but wanting to ensure they are mostly properly lubed for now, I am familiar with using a grease gun and modulating the pressure.

A few of you mentioned be sure you use the proper grease, so:
What is the recommended type/weight of grease to use to top off the wheel bearings?

Fortunantly, new brakes/backing plates are not that expensive, if you do it yourself.

[RLB348]

Where in the mountains of PA??

[Second Chance]

Where in the mountains of PA??

Forum hint: If you're replying to a particular member, use the “Reply With Quote” next to “Reply” (as I have done here). The person to whom you are replying will receive a notification and it helps others know whom you are addressing. You can also tag using their user name and the "@" sign: @RLB348. That will also generate a notification.

Rob

[timkoenig]

The Dexter video has me tempted to pump it full of grease and consider it good, however I am concerned with how much wear I have with about 17,000 miles in less than a year and how much grease was in there to being with.

So to be safe I am going to order new Timken bearings with races. When I tear it apart if the old bearings are smooth and not discolored I may just pack them and put them back in. Then I will have a spare set for next time.

I see many people saying to trust the engineers. I am a registered professional engineer and I trust the advice of experienced mechanics. Too may design decisions are based on cost and there is always the quality variability of bearing fabrication and axle assembly (nut torque and grease).

[Hoopy Frood]

This is all JMO of course: I have no real issue with the EZ-Lube feature of the Dexter/Lippert system, but feel that is unneeded. When was the last time you saw a
grease zerk on any automobile/truck wheel bearing housing? I also feel that you should do the wheel bearings every time you do the wheel bearings in your daily driver,
if it has them, which many do, especially trucks. Basically the grease is not going to "wear out" in the number of miles that most RV'ers put on their trailers. If I put
10,000-20,000 miles on my trailer per year, I'd check the bearings and brakes more frequently. But I don't, so I don't.

My only caveat is that a person should check the bearings condition, and grease amount when they first receive the trailer. From what I've seen the assembly of these
axles is done by standing back three feet and throwing the bearings at the spindles. Mine were gouged and dinged in multiple places. I cleaned them up with a fine stone,
but mine were not in bearing or seal mounting areas, but certainly could have been. I think once they're done properly they are good for several years of average RV
usage.

And one last thing: seems like many issues with brake and bearing problems occur shortly after brake and bearing services.