Packing bearings over full

JHZR2

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Curious about packing bearings. Im familiar with my old Mercedes cars - the grease to be used is to be measured by mass, with a fraction in the inner and outer bearing, and the rest in the cap. Very specific.

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[Linked Image from i.imgur.com]


I know that if those are overpacked above the intended mass, the oils tend to seep our past the friction-fit grease cap, and onto the wheel.

So enter today's case. Severe use on tropical roads with extreme grades and turns, including somewhat off-road use. This was just before the launch point, at a transition point from road to gravel, which probably had a 3-4" drop.

This bearing was a year old, and probably saw 25 full submersions in tropical salt water.

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Obviously no bearing buddy is in use. Grease seals must have failed. Planning on installing bearing buddies. But the facts of my car's bearings come to mind. Granted this trailer never goes faster than 25mph or further than 5 miles. There's no such thing as a highway where it is. But the trailer and boat are fairly heavy, and terrain severe.

So, a bearing buddy packs the inner and outer bearings, and all the intermediate space with grease, right? And then intent is to have a bit of over pressure so the water can't enter. But isn't that precisely over greasing? Won't the grease and bearing get overheated? It's exactly what one is supposed to not do on my Mercedes. So what gives? Does this over pressure that would get worse as the bearing and grease heat up, just seep out the rear grease seal? Do they drop grease all over as a result?

Perhaps compared to what I showed, life is extended even if overheated... but in ideal conditions are bearing buddies and all that extra grease actually good for anything?
 
Always packed as much as I could get in there for cars and have a bearing buddy on my trailer pumped full with grease gun.

Never had a failed bearing or an overheated one....can "too much grease" overheat a bearing????
 
Buy the real bearing buddies install them and follow the directions and never mind what you thought you know about greasing bearings because it isn't necessarily so You will need to buy and install shaft savers on the sealing surfaces on the axle so the seals will last and seal.
 
Tie Down Engineering spindles can "repack" by displacement via the rear port so that old grease is swept past both bearings. (On to a newspaper or paper towel).

With a Bearing Buddy ... you still hand pack the bearing, install the BB ... and top up via the fitting until the end piston strokes. Now you have a dynamic grease chamber ...

Unlike TDE, have to be careful not to keep pumping since it can pressure up on the rear seal.
A Bearing Buddy Can help prevent water ingress ...
(something I never have either)
 
Bearing buddies (get the real ones, as CT8 said) have a mechanism that vents excess grease/pressure.

Originally Posted by ammolab
Always packed as much as I could get in there for cars and have a bearing buddy on my trailer pumped full with grease gun.

Never had a failed bearing or an overheated one....can "too much grease" overheat a bearing????


The main concern on anything with a grease zerk is that Joe Hamfist is going to pump thirty shots of grease in it and blow the grease seal out. Bearing gets hot, grease thins out and then all leaks past the seal.

I imagine it's very difficult but not entirely impossible to do the same on a hand packed bearing.
 
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Surely you would pick that up before a wheel fell off ?....?

Your use sounds like what all boat trailers in NZ do. Trailer axles here use a seal that doesn't seal on the axle, they seal on the hub, with a s/s sleeve. If used with a bearing buddy they will just burp a bit of grease and not blow out a conventional seal.
 
Many years ago I had an old Scout. Every weekend I played in our local river. It was a constant wheel bearing battle. No matter what grease I used or seal type water always got in. Once it got in the bearings failed soon after.

During a busy summer I was pulling both axles completly apart and replacing the bearings and races every month.
 
A corroded bearing indicates seal failure. It doesn't take much to be a leaker. Power washing is another reason. Automotive wheel bearing seals withstand roughly 2 psi pressure. Those are sealed with 4 lips. I'm not that familiar with trailer bearings and their specific problems.
 
Originally Posted by Silk
Surely you would pick that up before a wheel fell off ?....?

Your use sounds like what all boat trailers in NZ do. Trailer axles here use a seal that doesn't seal on the axle, they seal on the hub, with a s/s sleeve. If used with a bearing buddy they will just burp a bit of grease and not blow out a conventional seal.


It went very fast. Heard noise roughly 100ft, was nearly at the launch, pulled in to investigate and the tough transition I think was the final straw.

As noted, this bearing was a year old.

Originally Posted by Kestas
A corroded bearing indicates seal failure. It doesn't take much to be a leaker. Power washing is another reason. Automotive wheel bearing seals withstand roughly 2 psi pressure. Those are sealed with 4 lips. I'm not that familiar with trailer bearings and their specific problems.


For sure it's a seal failure. The seals on these spindles I'm seeing aren't worth much. Here's the other side removed this am. Difference is the outer bearing had a lot more (not very good) "grease" in it than the other side.
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That said, I don't think it's power washing, unless the friction fit hub cap is to blame. We can't easily pressure wash the back side of the spindle. That gets effectively 0 psi flush, briefly.

But these are third world launch points. The trailer is submerged, and often the rear of the truck is in the water...

Originally Posted by CT8
Buy the real bearing buddies install them and follow the directions and never mind what you thought you know about greasing bearings because it isn't necessarily so You will need to buy and install shaft savers on the sealing surfaces on the axle so the seals will last and seal.


Im not so sure that "what I know" is so wrong, since the bearings in these Mercedes cars are often good well past 200k. I reused mine after my brake job, set properly, with the measured amount of grease. I've also seen firsthand when the grease isn't measured.

What doesn't happen with these is a bad rear seal.

There absolutely is a max amount of grease, for example, I found the SKF formula G = DB/10, where G is grease in ounces, D is bearing outer diameter, and B is bearing width.

There's something also to be said about the amount of grease for a given speed of the bearing. These never see over 25mph. But I'm not aware of that calculation.

So for us, full overpack, given speed/distance might be ok, while it may have bad consequences if used, say, on highway.
 
I never packed a wheel bearing overfull. Just made sure the ball or roller bearing cage was 100% full and an an amount in the outer shell and end. I never had a bearing fail and I'm sure I've done 100 in my lifetime of wrenching. Ed
 
I'm sure a heavy boat on a single axle trailer in severe terrain doesn't help. Especially the severe terrain. Both grades and turns.

But I also think the seal isn't working. The back side of the spindle is corroded and not smooth. So it can't seal.

I've also found that the help has NOT pressed the seals into the hub sufficiently...

Here's the one they installed yesterday. Two submersions.

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This is what the spindle looks like.

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Redid them both. Cleaned the one that was submerged in gasoline. Greased new bearings both side with calcium sulfonate grease. Took the boat out and pumped them up again at the launch point.

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Originally Posted by Chris142
Are you putting the seal on the spindle then putting the hub on?


That was me looking at the seal vs surface roughness of the spindle...

This was my first time messing with it. I installed the seal in the hub then the hub on the spindle. I think the prior "installers" pressed the seal on, then the bearing, then the hub... that would explain LOTS.

But the spindle is still corroded and rough. I went over it with a steel brush but no dice. I put a bead of grease outboard of the seal, and worked it in, which hopefully helps.

Got to where I needed, so all good for now. Two new hubs, bearings, and buddies.
 
One thing I do know the green Exxon Unirex N-2 grease is almost in a class by itself with regards to water and almost every other possible application.
 
Here's the type of seal we use on trailers, it's fixed to the axle, and spins in the stainless sleeve. Far better for salt water immersion than a standard wheel hub seal.

[Linked Image from fishing.net.nz]
 
I never followed weight with CV joints or tapered bearings, I packed in enough grease to fill the units/joints and then some to cover the boot/cavity/hub. I've never had a problem.

Now, ball bearings do call for a partial fill - especially sealed ones. I've overfilled Shimano bike hubs only to see grease seep out to places where it doesn't belong. Now, I use enough to tack the BBs in place and a final smear.
 
Originally Posted by JHZR2
Curious about packing bearings. Im familiar with my old Mercedes cars - the grease to be used is to be measured by mass, with a fraction in the inner and outer bearing, and the rest in the cap. Very specific.

I know that if those are overpacked above the intended mass, the oils tend to seep our past the friction-fit grease cap, and onto the wheel.

This bearing was a year old, and probably saw 25 full submersions in tropical salt water.

Obviously no bearing buddy is in use. Grease seals must have failed. Planning on installing bearing buddies. But the facts of my car's bearings come to mind. Granted this trailer never goes faster than 25mph or further than 5 miles. There's no such thing as a highway where it is. But the trailer and boat are fairly heavy, and terrain severe.

So, a bearing buddy packs the inner and outer bearings, and all the intermediate space with grease, right? And then intent is to have a bit of over pressure so the water can't enter. But isn't that precisely over greasing? Won't the grease and bearing get overheated? It's exactly what one is supposed to not do on my Mercedes. So what gives? Does this over pressure that would get worse as the bearing and grease heat up, just seep out the rear grease seal? Do they drop grease all over as a result?

Perhaps compared to what I showed, life is extended even if overheated... but in ideal conditions are bearing buddies and all that extra grease actually good for anything?


Those bearings failed for several reasons ( multiple parallel failure modes)

I'll tell you what they are ( just cant assign a percentage of contribution based on the pictures) but this is from well into the thousands of laboratory and field grade RCFA's for OEMs, bearing manufacturers and lubricant manufacturers.

The main problem with trailer bearings is the design but that's SAE and manufacturers- what they do is cost effective and "comfortable with the masses" , fits wheels/hubs so there is no possibility of changing it.

Everywhere else in the tapered roller world- if the load requires a bearing of "x" size on one end- it has that on both. This change in bearings changes all load parameters in travel, impact, turning and everything else. But that's not going to change because its cheap and adequate. Same with the shaft fit and then with running clearances against contact angles and geometry. This is why you have an "automotive" bearing. Every bearing manufacturer knows this but its unwinnable.

The problem with the grease isn't the grease- its the water (salt just makes it worse) where it churns and bonds then coats the metal ( mechanical working somewhat similar to putting sauce in hamburger meat then kneading it)- that attacks the bearing finish and metallurgy affecting the boundary characteristics starting with attacking the finish on the rollers ( that almost platiing type of wear you see)

Nobody is going to internally coat hubs, put proper seals on them or repack after each use.

Then of course the individual characteristics of your application ( water type, number of trips, weight, number of turns and a host of others)

Without significant effort the best method ( as many here have said) is to keep it full ( displace incoming as much as possible) and probably an annual repack. Use good seals and periodically check tolerance of the fit.
 
I don't buy boats. I buy a boat, motor, and trailer and it's going to come with Tie Down Engineering spindles or will buy another package elsewhere. The only way to easily displace old grease or contamination in 5 minutes … done
 
Been working great since 2006 … used the Bearing Buddy before that … they at least mitigate water ingress
TDE ported spindle and grease fittings "displace and replace" method is even better …
 
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