Bearing Maintenance
- Thread starter JWalker
- Start date
Jim.Allison
Well-known member
Ditto X2, You are right, if I might reinforce and add to your comment. Dexter warns about non compatible grease, EVERYTHING from stiffening/caking, liquefying and corrosion can be caused by non compatible grease according to their FAQ. If you are not the original owner, a brand new hand pack grease job is absolutely warranted. You cannot know the status of your bearings and there is a significant chance of failure when you need it the most. Time with the RV is difficult to come by, and standing on the side of the road with a blowout, broken spring shackles or burned up bearing is not my idea of spending time with my RV. Once your hubs are maintained to your satisfaction, the EZ-Lube system will certainly keep you going.
caissiel
Senior Member
The reason for turning the wheel is that a rolling bearing is designed to pump the grease through the rollers. If it don't rotate the rollers will block the flow of grease and the grease will take the easiest route and push the seal.
We use that theory in the industry to lube rotating equipment.
Actually bearings never fail. It's the invirontment that fails them,
Dirt, improper installation, moisture, lack of lubricant, overloading, over speeding.
Notice I never mentioned Chinese bearings.
One more bearing problem is shelf storage and handling damage has been observed as cause for failure. So if one carries spares, do not open the package before use. All bearings are designed equal and should perform well.
Never lost a bearing on my trailers. Even my utility trailer has been overloaded constantly.
We use that theory in the industry to lube rotating equipment.
Actually bearings never fail. It's the invirontment that fails them,
Dirt, improper installation, moisture, lack of lubricant, overloading, over speeding.
Notice I never mentioned Chinese bearings.
One more bearing problem is shelf storage and handling damage has been observed as cause for failure. So if one carries spares, do not open the package before use. All bearings are designed equal and should perform well.
Never lost a bearing on my trailers. Even my utility trailer has been overloaded constantly.
JWalker
Northeast Region Director-Retired
Ok, trailer is coming out of storage in 3 weeks. Going to hand pack bearings just to make sure.
-When you pull the bearings, what is the best solution to remove old grease from the bearings or is it best just to wipe them with a dry cloth.
-Is it best to get new seals from Dexter or can you get aftermarket?
-Does Dexter use a snap ring or cotter pins to hold the outside nut on? I heard some say that you should replace the cotter pin after every use. Is that true?
Thanks
-When you pull the bearings, what is the best solution to remove old grease from the bearings or is it best just to wipe them with a dry cloth.
-Is it best to get new seals from Dexter or can you get aftermarket?
-Does Dexter use a snap ring or cotter pins to hold the outside nut on? I heard some say that you should replace the cotter pin after every use. Is that true?
Thanks
danemayer
Well-known member
If you have EZ Lube zerk fittings, it'll be a snap ring because there's no place for the cotter pin.
jnbhobe
Well-known member
-When you pull the bearings, what is the best solution to remove old grease from the bearings or is it best just to wipe them with a dry cloth.
Parts cleaner is best but, Kerosene, Diesel fuel, or gas will work. Then use some Brake Kleen and air.
I would use aftermarket, usually a better seal. Chicago Rawhide or National are good ones. I use the ones for oil bath with a felt wiper but they are expensive and hard to find.
I usually replace cotter pins 1/8 X 2" Don't know if Dexter uses clips or pins, clips are usually reuseable.
Take the grease fittings out of the EZ lube. ( then you have to do it right )
Thats the best info I have Jamie.
Parts cleaner is best but, Kerosene, Diesel fuel, or gas will work. Then use some Brake Kleen and air.
I would use aftermarket, usually a better seal. Chicago Rawhide or National are good ones. I use the ones for oil bath with a felt wiper but they are expensive and hard to find.
I usually replace cotter pins 1/8 X 2" Don't know if Dexter uses clips or pins, clips are usually reuseable.
Take the grease fittings out of the EZ lube. ( then you have to do it right )
Thats the best info I have Jamie.
Jim.Allison
Well-known member
Lots of paper towels and what ever solvents are handy. I would use diesel because its cheap, get a $2 parts cleaning brush to help. I would use dawn or tide soap to wash the diesel out when finished only because its cheaper and its easier to slop a rag around in the hub, blow it out with compressed air. Be sure it is dry before reassembly.
Jim.Allison
Well-known member
If you have EZ-Lube; My EZ lube has a cage around the nut, look at it closely, it self explanatory as far as removal is concerned, take a photo for re-installation, DO NOT TAKE THE ZERK OUT. That is a direct path out of, or into the hub. If you feel your need to take the zerk out, then you need to replace the zerk with a plug.
mobilcastle
Well-known member
I have easy lube and I also have cotter pins-the hole for the pin is drilled off center.
porthole
Retired
However you clean the bearings, when you use air to dry them out DO NOT spin the rollers/cage, however enticing it may be to try it.
Jamie - if it was MY trailer and I was geting ready to do this, I would purchase new "quality" bearings and either of the two seals Jon mentioned.
And that would probably be the last time for 4 years or so that I would inspect / do maintenance on them.
If I do them correctly, I know I do not have to do the work every year.
Jamie - if it was MY trailer and I was geting ready to do this, I would purchase new "quality" bearings and either of the two seals Jon mentioned.
And that would probably be the last time for 4 years or so that I would inspect / do maintenance on them.
If I do them correctly, I know I do not have to do the work every year.
White gas (Coleman fuel) works well for cleaning bearings and doesn't leave any residue but not really safe because of the flammability. Stoddard solvent is much safer and works well for cleaning bearing and parts. You can get it at tractor supply and maybe at an auto parts store though I've never asked. I use a pan with enough solvent to cover the bearing and a stiff bristle brush to clean the bearing then I dry them off with air but as porthole said do not spin the bearing with air. The bearing cage is not strong enough to contain the centrifugal force off the bearings spinning at high speed and it can come apart like a grenade. There was a student at Cochise College where I used to work that spun up an aircraft gyro with shop air, they are designed to run on 4.5 to 6 inches of vacuum. The gyro exploded and killed him and even blew a couple holes through the hanger roof. A bearing can do the same thing. You can reuse snap rings but cotter pins should not be reused unless you have no other choice i.e. a repair on the road.
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Jim.Allison
Well-known member
Yes use the compressed air on the hub ONLY, Sorry I did not make myself clear on that statement. Ditto on the ejection of rollers or debris at tremendous velocities.
Thought this might be interesting to some who have had bearing failures. The bearing tells the story about why your bearing failed, were you listening. LOL.
http://www.timken.com/EN-US/product...Analysis-with-Lubrication-Reference-Guide.pdf
Thought this might be interesting to some who have had bearing failures. The bearing tells the story about why your bearing failed, were you listening. LOL.
http://www.timken.com/EN-US/product...Analysis-with-Lubrication-Reference-Guide.pdf
JWalker
Northeast Region Director-Retired
This was my thoughts also. From what I'm reading, the Dexter bearings might not be of the highest quality. I was thinking of ordering a better set and also a spare set. I guess I will need to see what model Dexter axles are on the trailer and order accordingly. Is there a good online store to get them from or over the counter location??
JWalker
Northeast Region Director-Retired
Great idea. It just so happens I have a gallon or two of the white gas sitting on the garage with no purpose. Thanks
jimpav
Well-known member
It seems that upon annual bearing inspection, after cleaning, there is always a dark colored area on the inner cone of the bearing. This is, I guess, caused by the electrolytic action of the bearing and the race after sitting over the winter storage. (explained in an earlier post). I looked on the Tinken bearing analysis sheets, and from what I could gather, if JUST discoloration is discovered WITHOUT any signs of pitting, then it's OK to just emery out the dark area and the reuse. Has anyone noticed these dark coloration spots after storage, and if so, what do you do???
justafordguy
Well-known member
After many hundreds of bearing repack jobs over the last 35+ years I have seen discoloration many times. I would always replace if in the budget because it could also be caused by over heating.
The dark color I assume you are talking about is is inter granular corrosion started by electrolytic action between the bearing and race. Many times it will appear as dark lines on the bearing or perpendicular lines on the race. Look for pitting with a magnifying glass and if you can lightly buff the dark spot or lines out you will probably be ok for another year. If the dark area is as wide as the bearing rollers running parallel to the race and especially if there is any bluing to the metal it's most likely over heating. In this case just replace the bearing and race. Also if you detect any pitting replace the bearing and race.
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jimpav
Well-known member
Good advise I will check them....thanks
porthole
Retired
You have a source for that?
Odds are, if your bearing rollers or cups have a color change it is either due to heat or poor quality. Either quality of the material or the fit between the 3 main pieces.
Either way, if you went far enough to clean the bearing and see this issue, then it is time to change all bearings (or 6)
FAA-H-8083-30, Aviation Maintenance Technician Handbook-General, FAA-8083-31, Aviation Maintenance Technician Hanbook-Airframe Volume 1 and AC 43-4A. The dark lines running perpendicular to the race or parallel with the rollers, (water marks) is usually caused by water between the bearing roller and the race of a stationary bearing. The water acts as an electrolyte or medium allowing for a small electric current to start between the two surfaces causing dissimilar metal corrosion and eventually pitting of one or both surfaces. In the early stages the marks can probably be lightly buffed off because the corrosion is on the surface. Inter granular corrosion is caused by the same electrolyte action but between different alloys within the metal itself usually caused by lack of uniformity during the manufacturing process i.e. improper heat treating. Aluminum structures like wing spars are more susceptible to this type of corrosion but it can and does occur in steel alloys. Inter granular corrosion can show up as a discoloration of the material or not at all but either way since it is corrosion that starts below the surface it can't be buffed out. The more technical name for these types of corrosion is electrochemical corrosion. Heat damage will cause a blueish color in the race or rollers and more advanced heat damage will cause galling. Galling is caused when the surface of the roller and surface of the race get hot enough to weld together and as the bearing moves or turns a layer of welded surface material is pulled up from the race or off of the roller.
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