Bearings and Seals

[Mexray]

It's always a good idea to ALWAYS replace inner hub seals every time your brakes are serviced or the hubs are removed to repack the bearings, etc...

New seals are 'cheap' in the overall scheme of cleaning/repacking wheel bearings or brake repairs...

New seals usually have a coating around their exterior, bore/mating surface that acts as a 'sealant' to insure that no lubricant leaks from this area - re-using an old seal that has been pressed out of it's bore may damage the 'sealant' outer seal surface coating...

There is almost always a 'part number' on the old seal that can be 'crossed over' to a vendor's brand...or you can go to a bearing house in your area to get replacements if you take them the old seal to identify...

Once identified, it's probably not a bad idea to keep a new seal or two in your 'road spares' box - I like to put mine into plastic freezer bags to keep any dust away...when it comes time to repack you bearings, you'll have a new sample to buy additional stock if need be...

[centennialman]

Originally Posted by AirsDream

Most "experts" will tell you never to use a compressor to blow grease or solvent out of a bearing ... risk is that it will spin a race or roller (or ball) up to a very high speed (dry) and score / gall it. I'm not sure whether those experts are right, but it seems to be a bit of received wisdom. I personally have occasionally ignored those experts, but a) only using pretty low air pressure, while b) physically holding everything tight in an absorbent rag so that nothing can move. No bearing failures have resulted, but it's probably tempting the gods. As always, YMMV.

That's good advice! I did hold the bearing in a rag and the rollers were pretty stationary while I blew it out.

Thanks!

[Kevin245]

Originally Posted by CrawfordGene

I don't believe all the grease is forced out of the bearing with compressed air unless solvents have been used before the air is applied. There's a thin film of grease left by the compressed air and thus the rollers are not dry. They are also under no stress. These bearings undergo a lot of stress rotating at high speed in normal use at temps a bit over 100˚ in summer. Compare that with a roller rotating a little under no stress with a greasy film on it at lower temps. I suppose when they are hand packed with grease, they roll dry until the grease is worked into the bearing.

I worry more about which solvent to use and what its effect is. Do small amounts of solvent remain in the bearing and compromise the grease? What is the effect of rolling the rollers when only solvent is in the bearing? Just how tough are the rollers?

This is an interesting discussion and will probably make all of us better at this.

Gene

Gene,

You’re absolutely correct. This is a very good topic that’s generating valuable discussion. I’m thinking that maybe we should consider some technical posts, or possibly a hands on demonstration at some rallies from time to time.



I agree that unless solvents are used to clean the bearings the likely hood of spin related damage using compressed air is minimal. What I've seen before that concerns me is when someone solvent cleans a bearing set, and then spin dries them with compressed air to remove residual solvent. With no lubrication on the faying surfaces, scratching will occur if dry spinning occurs. Even slight scratches in the surfaces increase friction which generates heat and can lead to failure. I’m not saying that every bearing treated this way will fail, but that treatment of this type should be avoided. When air drying, make sure the parts don’t rotate, and the air source is clean.

The components of a tapered bearing set are hardened for wear and increased service life. The inner race, outer race, and rollers are usually harder than the cage, if the cage is hardened at all. Many bearing failures occur when the cage becomes worn due to lack of lubrication, or debris. This is because of sliding friction that occurs between the rollers and the cage, it is inherent with the design and can’t be avoided, but it can be minimized with propoer care and maintenance. When cage pocket wear occurs it allows the cylindrical rollers to move around in the travel path causing more heat, and wear. This can go on for some time depending on frequency and length of use, and the degree of damage. All it takes is a nick, scratch, physical damage, or debris between any of the contact surfaces to initiate the failure process.

The issue of solvent residual interacting with newly applied grease is a concern, but I’m not aware of any specific history, and solvents are widely used for this purpose. The key is drying, or removing the solvent prior to re-packing.


I'm kind of AR about bearings and brakes. My experience has always been to:

1. Remove excess grease with a lint free rag – This includes the outer races located in the hub

2. Solvent pre-clean

3. Solvent clean

4. Solvent rinse

5. Dry with a lint free cloth

6. Air dry for an hour or so before repacking. I wrap the bearings in a clean cloth and lay them out on a warm surface to dry before reassembling.

7. Final visual inspection

8. Repack and re-install

I don’t own a bearing packing tool (I’m cheap), so I do mine by hand using the palm method which does not involve rolling the bearings.


I'm running tapered bearings in my old F150 that have over 300,000 miles on them, and they look like new.

Regards,

Kevin

[safari62]

[quote

As for Chinese vs. US bearings, I think Chinese made bearings can be as good as any others if the US company is carefully watching the process and making sure the bearings are made correctly. The latest story about Chinese made Goodyear Marathons was that the Chinese tires weren't up to Goodyear standards, so they cancelled the contract and are making them here again. Junk can be made anywhere including the US. Nonetheless, we avoid Chinese made stuff with strange brand names. In the 19th century, Europeans complained that US made things were poorly made just like we complain about Chinese made things. Good or bad stuff can be made anywhere; it depends on the manufacturer and their standards. Badly made Chinese products sold by US companies are just as much the responsibility of the US company as the Chinese.

Gene[/quote]
As to your first point, not true and not even the point. Chinese Goodyear Marathons were failing and sales fall off. Chinese Marathons not up to our standards. That's a news flash. Chinese drywall is poisoning people. Chinese dog food is killing pets and so on and on.

American companies shift production to China because they have cheap labor and zero environmental standards. In the process our jobs disappear, the balance of trade shifts overseas and we lose our manufacturing base.

Do American Companies worry about being responible about the quality or saftey of chinese products? Looks like it is just another way to pass to buck and place the blame on the sub contractor.

Europeans probably complained about our products BECAUSE they were substandard at that time. We got better at producing higher quality items and even made the best cars for a time. That did not last.

If you want to put low budget bearings made in Zanswon China under your expensive Airstream it's a free and cheap country. For now.

But you have a choice to buy made in the USA parts. I am sure they are a higher quality product at almost the same price. The guy at the Timken plant would be happy too.

After the timken Plant closes we will not have that choice either.

[Gene]

Originally Posted by safari62

As to your first point, not true and not even the point. Chinese Goodyear Marathons were failing and sales fall off. Chinese Marathons not up to our standards. That's a news flash. Chinese drywall is poisoning people. Chinese dog food is killing pets and so on and on.

American companies shift production to China because they have cheap labor and zero environmental standards.

I'm unsure what you mean about my "first point". Do you you mean every Chinese made product is junk? I agree that some are junk, too many are junk, but not that all are. There were complaints about Marathons made elsewhere than China, notably Canada. It seems that Goodyear's tire design is not up to the standards of other tire manufacturers and I wouldn't buy Marathons if they were made down the block from me.

I know why companies shift production to China, but cheap labor and zero environmental standards do not necessarily equal bad products, but I think they increase the likelihood that the products will be bad.

I am as frustrated as anyone with bad products, and as I said, if I have a choice, don't buy Chinese ones. Long before China became a major exporting country, people complained about bad American products and people said "they don't make them the way they used to". It's generally true that American made cars and trucks were the best in the world or among the best in the world. That changed too. As for American made bearings, when I needed bearings as soon as possible in northern Minnesota while on the road, I took what the only after market dealer within 100 miles got me. They were Timkens.

It seems we have become diverted from bearings.

Gene

[Kevin245]

Getting back the the subject at hand.

You wanna see a bearing?

Check out this beauty I have in my office.

It came off a machine press project we worked on several years ago. It measures 12" across, fits a 7" shaft, and weighs in at a healthy 52 pounds.

Regards,

Kevin

[Silverhobby]

Originally Posted by tkowalyk

I have a 2006 Safari -- with neverlube bearings. The maintenance recommends lubing every 12 months -- but I have read that this is not necessary -- and 3 - 5 years is recommended?

Any advice or opinions welcome.

Tom,
While the grease may last longer than 1 year, the advice is to check the brakes, bearings, and the springs securing the brake shoes. Anything can happen over time. It's just a good safety check to insure you don't have trouble while on the road, when you'd rather be having fun.

[billiards]

will just jump in on this forum topic and hope for tolerance......my first job, which begin in my teen years, was in a brake and front in shop (Omaha Nebraska) and considered the best but surely not the least expensive....the learning and trade of several years has served me long after changing vocations.....my first assignment was cleaning and repacking bearings from the autos having wheel off repairs (brakes/etc.) the following was typical of the process:
bearings cleaned w/solv., wiiped dry with cotton cloth, inspected and replaced both race and bearing if nicks or metal missing, bearings packed by hand spreading grease on outer roller surface also, seal replaced only if missing sections of rubber, bearing adj. was tightened to tight/back of/retightened and keyed, if no a match back of to first castel. by not loading hub with grease, it is not that critical to have a new or like new seal, water...well not much of a factor unless one would run in a couple of feet of it....if it makes one feel better go ahead and replace the seals, cost will not break the bank.....i only post this as i know the amount of autos that went in and out the door with out a problem, if there was any doubt of failure it would be replaced, if you knew the owner of this shop, his moto was i dont want the business if i cannot do it first class. (most important is not to mix grease, clean and replace, the thickener does always like each other) for what its worth