How much grease for wheel bearings?

[IT_Burnout]

I have run into this problem more then once over the years with boat and camping trailers. Over greasing zerk fitting on wheels and pushing grease through the seals and getting grease into brakes.

I purchase wheel bearing grease in tubes for my grease gun and I am just putting in a couple pumps in maybe every 1000 miles.

Wondering how much and how often is the right amount for greasing wheel bearings? Am I putting in to little or to much? Wondering what others are doing to keep things greased up good with out over doing it.

Thanks in advance for your input.
Bob

[time2roll]

x-ray vision:

https://www.youtube.com/watch?v=XT0RKDGgDm8

The unknown is the volume of the air pocket between bearings along with never knowing if any grease is on the brakes until you try to stop.

[BB_TX]

Huntindog wrote:

BB_TX wrote:
If you have the EZ Lube hubs, the zerk is there to purge the bearings and hub of old grease and replace it with new grease. BUT. You must do it correctly. And that means using a hand pump and pumping the grease very slowly while continuously turning the wheel. The grease is ported behind the inner bearing, then flows thru that bearing as it is turning, thru the hub, thru the outer bearing, and out the front of the hub around the zerk. That pushes all the old grease out. When you see new grease coming out the front you know all the old grease has been replaced. If you pump too hard or don't turn the wheel the pressure may push grease past the seal.

A pump or two does nothing toward getting new grease to the outer bearing. It takes a lot of grease to do it correctly.

Google ezlube for videos and how-to information if that is what you have.

Not quite correct.

Here is the facts on how this works.

The zerk feeds a hole that will attempt to grease the inner bearing. How well this will work depends on the condition of the seal/hub interface, and the skill of the person doing it.
He needs to slowly turn the wheel while steadyling pumping the grease... It is working blind as you cannot see what is really going on in there. Is the fresh grease getting evenly distributed in the bearing? Or are spots being missed/skipped? Is the seal really in good shape? or is grease seeping past it onto the brakes?
One simply cannot be sure. All seals age and leak at some point. Sometimes a brand new seal is nicked during installation... Without superman vision, one cannot know.

But the potential problems don't stop there. In order to grease the outer bearing, the grease must travel thru the inner bearing, and the hub cavity to the inside of the outer bearing. This takes a considerable amount of grease... Several tubes each time for a dual axle TT... That's right EACH TIME... The video on Dexters site is misleading. The dirty grease that they show exiting the hub is only from the outer bearing. The dirty grease from the larger inner bearing is still in there some where.... Some of it may have even made it to the inside of the outer bearing!!
Without xray vision, one cannot know exactly where it is... So one must keep pumping and pumping and pumping,, until a second section of dirty grease emerges. Even then one cannot know if all the dirty grease is purged. It is a long trip for the grease, and it probably will not travel evenly around the hub..
With all of the pumping that must be done, a compromised seal will likely fail greasing the brakes... But hey, I hear that well greased brakes never wear out.:B

So you see it is not as simple as the marketing makes it out to be.

Now knowing all of the facts, if one still wants to use this "feature" I wish them well.

Interesting description of the process. You say without xray vision you cannot see what is going on. And yet you are describing an exact grease flow thru the bearings and hub that can't be seen. Is that info from some legitimate research study on the system? Or is this your interpretation of the process? Would like to see a link to a research study if available.

[time2roll]

I just did mine at ten years with new hubs and rotors for disk brakes 😉
Grease was still mostly red and all bearings were fine.

[BFL13]

fj12ryder wrote:
12,000 miles or yearly. Just ain't gonna happen. A CYA by the builders.

Same with me. I can't afford for the shop to do it that often (every year) and can't do it myself. So howinheck are you supposed to know when to take it in?

After a few of those expensive jobs, I let it go for longer, and after a some years, I finally noticed I had no trailer brakes. I could stop ok with just the truck brakes doing all the work--thank goodness for them being up to snuff. This must have been the case for months and months if not longer. I know you are supposed to check for that using the brake controller and no truck brakes every time out, but I must have neglected that not so little thing. That is how I finally figured out I had a problem. I also didn't have the trailer come around because the truck stopped first--a 5er thing I guess, don't know)

I took it in to "my" RV shop and they showed me the brake shoes all skinny and in pieces and worn metal everything else all around. I had no brake controller issues and voltages and amps were ok- just no stopping the trailer.

It turned out to be cheaper to get all new everything, since that included new already greased bearings, so I didn't have to get that done, but it was a huge pile of money. I didn't save anything compared with just keeping up with regular maintenance, plus I was going around for months and months with no trailer brakes and didn't even know it, because the truck was stopping us ok.

The thing is, you have no way to know what is really going on in there under the hubs, so you are a captive of the whole industry, who just wants your money. You can't pick when to go and get the work done based on any evidence you can use to know when it is really time to get it done.

Whine, sob. But that is how it is! Hate that! 😞

[ScottG]

time2roll wrote:
None through the zerk is best IMO.

If properly greased and adjusted at the last service the grease will last just fine until the next service.

Totally agree.

[fj12ryder]

12,000 miles or yearly. Just ain't gonna happen. A CYA by the builders.

[Huntindog]

Quite a few of us think that the Dexter recommendation of 12K is a generic one. If you read the manual, it does NOT differentiate for different types of service.. IOW, Boat trailer axles get the same recommendation as TT axles... Even though the conditions that they operate under are way different.

[BFL13]

The Dexter manual since at least our 2003 trailer has always said you have to clean off the old grease and check the bearings for spalling etc before you regrease. Then it says to check the brakes every 12K or yearly whichever comes first. You need to take the hubs off to check the brakes. You need to take the hubs off to clean the old grease off the bearings.

Strangely enough, the interval for doing that is the same as for checking the brakes. This leaves regreasing with the hubs off--ie manually.

There is never, ever an occasion in the manual for ever using a grease gun on the zerks. Unless you park your trailer in a river so now it is like a boat trailer.

So why oh why did they put those EZLube things on an RV? "Sales" said it would look good in their ads as a neat feature.

Bottom line-- if you own a grease gun and get the urge to use it on your EZ Lubes RV, lie down till the feeling goes away! Do the bearings manually and inspect them while clean before regreasing like it says. Do the brakes like it says at the same time while the hubs are off.

Why do the brakes so often even if you haven't gone very far in a year? Dexter tech support told me the reason is that they are air- cooled and moisture can get in while you are parked--especially on wet grass. So the brakes can get rusty even though hardly any miles on them. So the brakes are setting the pace for how often you regrease the bearings and how-- ie, manually while the hubs are off.

No reason to ever grease the bearings more often than that (unless you park in a river---but that can't be too good for the brakes either 🙂 )

[fj12ryder]

IT_Burnout wrote:
You bring me back to one of my original thoughts on this subject. I have run many cars well over 200 K miles over the years. When new brakes are required I usually have bearing checked or repacked since I don't do much of the work myself any more. But that is sometimes 50-60K miles between intervals. Is it really necessary to do so much more bearing maintenance on a trailer?

Bob

Some of us don't think pulling and repacking bearings every year or two years is necessary. I pulled the hubs on my 2010 Fuzion for the first time last year, and everything was hunky dory. I have the EZ Lube setup and filled the hubs after the first year. I've done nothing since until last year.

I honestly don't see the real need for the EZ Lube bearings. The grease can't go anywhere so it doesn't need new grease periodically. The miles put on a normal trailer doesn't really qualify as heavy duty. I have nothing against the EZ Lube system, just don't see the need to add grease on a regular basis. As you have noted you don't lube your car's wheel bearings, why would the trailer bearings be that much different. "If it ain't broke, don't fix it."

[IT_Burnout]

Huntindog, Yes I did miss it, you must have been posting while I was typing my response. I did go back and edit my post. You do bring up another side of the whole issue, that I really never considered.

[Huntindog]

IT_Burnout wrote:
Everyone thanks so much for the input.

The nice part about this forum is you can ask and find people with way more knowledge then you have on a subject. This was an eye opener for this old boy. I do have the Dexter EZ lube setup and I guess I didn't have a clue to the required maintenance for them. I did as suggested a search on you tube
and found a video from Dexter and it stated jack it up and rotate the tire slowly while pumping grease slowly until you see the new grease come out the front. That would have been the last thing I would have done fearing blowing grease out the seals. I guess that will be my new spring project each year from now on. Who says you can't teach and old dog new tricks. I am humbled one more time.

I learned something, thanks again.
Bob

Umm.. Did you miss the post I did right before your last one?

The Dexter video only shows part of the story.

[IT_Burnout]

Everyone thanks so much for the input.

The nice part about this forum is you can ask and find people with way more knowledge then you have on a subject. This was an eye opener for this old boy. I do have the Dexter EZ lube setup and I guess I didn't have a clue to the required maintenance for them. I did as suggested a search on you tube
and found a video from Dexter and it stated jack it up and rotate the tire slowly while pumping grease slowly until you see the new grease come out the front. That would have been the last thing I would have done fearing blowing grease out the seals. I guess that will be my new spring project each year from now on. Who says you can't teach and old dog new tricks. I am humbled one more time.

Huntindog, I noticed your post right after I posted mine and came back and edited. You bring me back to one of my original thoughts on this subject. I have run many cars well over 200 K miles over the years. When new brakes are required I usually have bearing checked or repacked since I don't do much of the work myself any more. But that is sometimes 50-60K miles between intervals. Is it really necessary to do so much more bearing maintenance on a trailer?

Bob

[Huntindog]

BB_TX wrote:
If you have the EZ Lube hubs, the zerk is there to purge the bearings and hub of old grease and replace it with new grease. BUT. You must do it correctly. And that means using a hand pump and pumping the grease very slowly while continuously turning the wheel. The grease is ported behind the inner bearing, then flows thru that bearing as it is turning, thru the hub, thru the outer bearing, and out the front of the hub around the zerk. That pushes all the old grease out. When you see new grease coming out the front you know all the old grease has been replaced. If you pump too hard or don't turn the wheel the pressure may push grease past the seal.

A pump or two does nothing toward getting new grease to the outer bearing. It takes a lot of grease to do it correctly.

Google ezlube for videos and how-to information if that is what you have.

Not quite correct.

Here is the facts on how this works.

The zerk feeds a hole that will attempt to grease the inner bearing. How well this will work depends on the condition of the seal/hub interface, and the skill of the person doing it.
He needs to slowly turn the wheel while steadyling pumping the grease... It is working blind as you cannot see what is really going on in there. Is the fresh grease getting evenly distributed in the bearing? Or are spots being missed/skipped? Is the seal really in good shape? or is grease seeping past it onto the brakes?
One simply cannot be sure. All seals age and leak at some point. Sometimes a brand new seal is nicked during installation... Without superman vision, one cannot know.

But the potential problems don't stop there. In order to grease the outer bearing, the grease must travel thru the inner bearing, and the hub cavity to the inside of the outer bearing. This takes a considerable amount of grease... Several tubes each time for a dual axle TT... That's right EACH TIME... The video on Dexters site is misleading. The dirty grease that they show exiting the hub is only from the outer bearing. The dirty grease from the larger inner bearing is still in there some where.... Some of it may have even made it to the inside of the outer bearing!!
Without xray vision, one cannot know exactly where it is... So one must keep pumping and pumping and pumping,, until a second section of dirty grease emerges. Even then one cannot know if all the dirty grease is purged. It is a long trip for the grease, and it probably will not travel evenly around the hub..
With all of the pumping that must be done, a compromised seal will likely fail greasing the brakes... But hey, I hear that well greased brakes never wear out.:B

So you see it is not as simple as the marketing makes it out to be.

Now knowing all of the facts, if one still wants to use this "feature" I wish them well.

[Cobra21]

Matt_Colie wrote:
Bob,

If you have the spring loaded Bearing Buddies, then only pump in grease until the spring is compressed.

If all you have is grease caps with Zerks, then it is anybody's guess. Yes, you can blow out the grease seals with a grease gun.

Matt

I agree for spring loaded.

[BB_TX]

Mandalay Parr wrote:
Over greasing a bearing will make run hot.
Best to fill the bearing 1/3 full.

EZ Lube Hubs (and bearings) are packed completely full of grease and do not run hot, even in temps well over 100 degrees. Have run at 65-70 for hours in temps of 102-105 and hubs are warm to the touch.