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New Wheel Bearings could use more grease.

JonJay

Well Known Member
At 90 hours, I am picking away at my regular maintenance items to reduce the time I am actually down for my up coming Conditional Inspection. I did not grease my wheel bearings before the first flight.
Although they where "pregreased", they where not greased very well. I would recommend that you pack them before you take that first flight.
I would not have wanted to go too many more hours on them. Perhaps this has been noted before, but it passed me by.
 
Good thread.

I just got done going through the brakes on a 10. I noticed the holes for the cotter key were not deburred causing metal shavings to form when the aluminum cap slid across the burrs. Sooo, it was a good time to pull everything apart, inspect the brake pads, pins, backing plate, bearings for grease, and look for any abnormalities.
The caliper bolts were a tad loose so I pulled them out and used Loctite & torqued.

After 150 hours, a little more than 1/2 of the pad life left. Not bad wear, IMHO, but after reading another thread about the 10's pads being hard to come by I ordered a set just in case. I hate waiting for UPS.
 
At 90 hours, I am picking away at my regular maintenance items to reduce the time I am actually down for my up coming Conditional Inspection. I did not grease my wheel bearings before the first flight.
Although they where "pregreased", they where not greased very well. I would recommend that you pack them before you take that first flight.
I would not have wanted to go too many more hours on them. Perhaps this has been noted before, but it passed me by.

It is funny that you brought this up. I was just discussing things that we need to do before moving the plane to the airport. The wheels were greased when I got them but I didn't think they were greased well and we need to pack all the wheel bearings before we move the plane. Thanks for confirming it.
 
Someone once told me that the grease that comes with new bearings is just there to preserve them until you put the "real" grease in. Seemed believable to me, so I repacked my bearings before I ever installed my wheels.

mcb
 
Someone once told me that the grease that comes with new bearings is just there to preserve them until you put the "real" grease in. Seemed believable to me, so I repacked my bearings before I ever installed my wheels.

mcb
Makes sense. If they where packed in wax paper, like you normally see new bearings, it would be obvious to most people. However, they are supplied installed in the wheels. I think this makes them an easy thing to overlook.
My bearings defineatley had more grease than just a protective coating, as I have seen on packaged bearings, still, not very well packed.
 
The grease that is in the bearings, as shipped in the kit, is not adequate and should be cleaned out and the bearing properly repacked before assembling the wheels and brakes on the plane.

Roberta
 
The grease that is in the bearings, as shipped in the kit, is not adequate and should be cleaned out and the bearing properly repacked before assembling the wheels and brakes on the plane.

Roberta

Here is my as-received bearing from Cleveland, installed on gear yesterday:


Roberta, how do you know it's not adequate? What IS adequate? Not all bearings should be packed 100% with grease - should these?
 
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Here is my as-received bearing from Cleveland, installed on gear yesterday:


Roberta, how do you know it's not adequate? What IS adequate? Not all bearings should be packed 100% with grease - should these?

I would suspect mine looked about like that when new. I got 90 hours on mine with no adverse affects or signs of where, but there was not much grease left in them. I think Roberta's advise is sound.
However, I have never heard of any bearing failures and I would bet that I am not the first person to overlook this. One should reasonably clean and repack wheel bearings at least every 100 hours, depending on environment and usage, and/or at each conditional inspection. So, is it adequate, was for me, but.....
Might be an interesting question to throw out there, "has anyone ever had to replace their wheel bearings?"
 
Gary Bricker

Avery sells a bearing packer that is great to use and you will get the correct amount in the bearings. They should be packed from one end until the grease goes out the other end. This packer does this very easy. When the bearing is packed this way the grease is inside the cage where it needs to be.
 
Mine did not have nearly that much grease in them. Not knowing the type of grease, how old the grease was, or how adequately they were packed, I would recommend that they be cleaned and repacked with the correct grade of grease to ensure adequate coverage of the bearings. Seems like easy, cheap insurance to me. Your plane, though. Do what you think is best.

Roberta
 
Avery sells a bearing packer that is great to use and you will get the correct amount in the bearings. They should be packed from one end until the grease goes out the other end. This packer does this very easy. When the bearing is packed this way the grease is inside the cage where it needs to be.

The URL to that is:
http://www.averytools.com/p-188-bearing-packer.aspx

I use it any time the wheels come off for any reason - total grease replacement in about ten seconds.

Lots of pics of it at:
http://images.google.com/images?hl=en&q=bearing+packer&um=1&ie=UTF-8&sa=N&tab=wi
 
Sears stores in my area sell the Lisle bearing packer. It works great by the way.
 
Wheel Bearings

Definitely use the bearing packer and the recommended lube. Also, be careful to keep moisture out of your bearings! I dunked my wheel in water to verify no leaks in the tube (they were squeezed by the last guy that installed them and went flat) and later found I had ruined my bearings and races. They sounded like gravel spinning when I landed! A buddy was on his bike near the airport when I landed and told me about it. Had to remove and replace the races and bearings in that wheel. I talked to the manufacturer and they saw the pictures and said "moisture contamination" which seemed strange. I don't fly in the rain..... When I was putting the new tire and tube together I almost did it again and realized how the moisture got in there and ruined the bearings and races....:eek:
Not that you couldn't leave the bearings out and dunk check the tube, then carefully dry it out before reinstalling the bearings...... I just wasn't that smart! :(
 
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Greeezie

Although I didn't take a photo, the red dust caps installed in the bearings were labeled "MIL-PRF-81322", which is what is recommended by Cleveland. I would expect that this is the grease actually used on the bearings, in addition to being what is recommended.

Mobilgrease 28 is one grease that meets or exceeds this spec (but its red in color, not white like Cleveland's factory grease). Mobil says that greases shouldn't be mixed, but is this the chemists or the lawyers talking?:rolleyes:

Do I really need to clean off the original grease (seems like a huge pain and requires degreasing machine) if they're both MIL-PRF-81322 greases?
 
recommended lube?

Avery has the bearing packer on sale, btw.

Anyway, my question: What is the recommended bearing grease?

Thanks,
Greg
 
Shell's Products

AeroShell Grease 5
Wheel bearing and engine accessory grease
Microgel thickened, mineral oil base
Combines high load-carrying ability with excellent resistance to water and high temperatures. It inhibited against corrosion and oxidation, and has a useful temperature range of -23?C to + 177?C. Used primarily in aircraft wheel bearings and engine accessories operating at high speeds and relatively high temperatures.

AeroShell Grease 22
Versatile multipurpose grease
Microgel thickened, synthetic hydrocarbon oil base
Corrosion inhibited and fortified against oxidation, it has excellent anti-wear properties, load-carrying capacity and water resistance, plus a wide useful temperature range of -65?C to +240?C. Recommended for aircraft wheel bearings, engine accessories and airframe lubrication, and for anti-friction bearings operating at high speeds and at high or low temperatures.
 
22

AeroShell Grease 5
Wheel bearing and engine accessory grease
Microgel thickened, mineral oil base
Combines high load-carrying ability with excellent resistance to water and high temperatures. It inhibited against corrosion and oxidation, and has a useful temperature range of -23?C to + 177?C. Used primarily in aircraft wheel bearings and engine accessories operating at high speeds and relatively high temperatures.

AeroShell Grease 22
Versatile multipurpose grease
Microgel thickened, synthetic hydrocarbon oil base
Corrosion inhibited and fortified against oxidation, it has excellent anti-wear properties, load-carrying capacity and water resistance, plus a wide useful temperature range of -65?C to +240?C. Recommended for aircraft wheel bearings, engine accessories and airframe lubrication, and for anti-friction bearings operating at high speeds and at high or low temperatures.

Cleaveland recommends the second one (AeroShell 22) - but they seem to have upgraded their web site, and the links don't work...:mad:

They had another specific grease recommendation, but I can't see it due to the web site...

gil A - hate it when big companies (Parker) screw up their web sites in the name of standardization...:)
 
Grease

I use Aeroshell 22, it is synthetic and works great. DONT get any on the tube itself. I wipe down the metal rings, pat down the fuzzy pad, spray the bearing with a siphon sprayer with mineral spirits, and let them dry. Then I pack them using one of three methods, the cone, the hand pressure pot or simply by hand. I then insert the bearing in the race with a little 22 on the outside of the bearing, I then do the "secret trick" of glopping some 22 down on the outside/top of the bearing (if the wheel is on the ground looking up) and put the metal ring in and clean up the excess. I then put all the other parts in and make sure the little ring is seated. WARNING! Some of the metal washers that cover the bearing have different ID's and you need to go by the book.. not how they came off because it may of been put on wrong.
Best
Brian
ps.. dont spin them with air pressure with your air chuck.. Yes I know it's fun but you should not do that. If you have to replace a bearing... replace the race as well. If anything comes close to catching my fingernail then I replace the race and bearing. Look for discoloration too... I'm always available for questions...

Best
Brian
 
I just replaced my tires at 150 hours and had the first look at my bearings since the original setup packed with Aeroshell 5.
They showed no wear.

I repacked the bearings along with new brakes & tires.

Back to flying!
 
Cleveland wheel bearing grease

For what it is worth, I sent an e-mail to Cleveland asking if the bearings came ready to use right from the box. Their reply:
"The wheel bearing grease that came from the factory is Mobil Aviation Grease SHC 100, which is packed & ready to use. The SHC is used across the board with our wheels.

If you would like to change the grease, clean all of the grease from thecup & cone bearings before installation.

Please do not mix & match greases."


John Ciolino
RV-8
Almost ready for trip to airport
 
Like I learned a bunch of years ago in A&P school, to pack bearings you "don't need no stinkin special tools" :D Just something else besides your hands you'll have to clean. Uses much less grease also.

Check out http://www.fullsizebronco.com/forum/showthread.php?t=75784 and I recommend the Aeroshell 22 for aircraft.

That's how I pack bearings as well, as taught by the Air Force. I don't water rinse though...just solvent, then blow out the solvent with compressed air. If you get all of the solvent out, you don't need water. I have several bearing packing tools, and have found that none of them do as quality of a job as doing it by hand. All of them waste too much grease.

I do recommend wearing some nitrile gloves for the job though....as clean up is much easier. I have always used aeroshell 5, but I'm considering a change to 22.
 
I just did my bearings at annual inspection now. About 100hours on them. Found some discoloration and some slight surface roughness at the discoloration.I also really struggled to get the wheels off. The races polished out with some 2000 grit paper. Yes sounds terrible doesn't it ! Actually it polishes the race surface well.
You probably ask why just not replace? Well I don't have a spare set and want to get the annual done . I will order a set for the next annual.
A aircraft mechanic at the airport said the were acceptable.

Here's the biggie... I wont use any aeroshell grease again. It just doesn't seem to be a very "water resistant grease" type grease.
Next time I'm going to use Yamaha HP waterproof grease. I have used it in other applications and have had 100% anti corrosion protection with it.
just my 2c.
 
Packing bearings

I was always told two golden rules for lubing bearings.

1) Do not "pack" the bearings to 100%. In fact more bearings fail in industry to having too much grease packed in them and its worse than having none at all.

2) Never spin dry a bearing with compressed air.

I think the "lack of grease" seen in new bearings is because they are in fact in fact greased appropriately for use. Over the years I have used this approach (never had a bearing fail in 30 years) and often put more than enough in but only as long as it could either escape or there was at least enough rooom (btween any seals) for the grease to move away from the rollers.

As a guide I was told that for a ball bearing (with seals) no more than 60% of the spaces between the bearings should be stuffed with grease.

Now of course wheel bearing on an airplane does not see a lot of use so it probably is likely to fail due to corrosion than overheating so maybe a little more grease is warranted in this application.

FWIW

Frank
 
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