Rear Wheel Bearing going bad ?
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what type of vehicle is this?
I wouldn't neccessarily jump to that conclusion: most of the time a noise like that in the rear is simply a rust fleck or something that is wedged beween the rotor splash shield. a bad bearing normally makes a "bad" noise through out its entire rotation and can also be validated by mounting the tire and trying to "wobble" it.
It should be a sealed hub assy, no seals. If a bearing is going bad, you can usually hear it growling while driving, especially when you are turning and the vehicle is putting load on whatever side bearing is going bad.
When you rotate the hub does it feel smooth with a little drag to it? If the hub spins too easy or is notchy or has play in it than the bearing is bad, otherwise the bearing is good.
Originally Posted By: KrisZ
When you rotate the hub does it feel smooth with a little drag to it? If the hub spins too easy or is notchy or has play in it than the bearing is bad, otherwise the bearing is good.
Notchy is a good word. I have a 99 Toy Avalon FWD w/95k miles. The rear wheel hubs do not have any play but they are definitely notchy. Off the car, it feels like the ball bearings have flat spots when you rotate by hand and you can hear it. They are hard to rotate but that could just be the right amount of preload. I've nver rotated a new assembly so I don't know what it should feel like. One of the hubs has been leaking grease. There is a wet spot on the bottom with the usual build-up of grime. Must be a bad seal.
I'm guessing at 95k I should replace both hubs. Agree?
When you rotate the hub does it feel smooth with a little drag to it? If the hub spins too easy or is notchy or has play in it than the bearing is bad, otherwise the bearing is good.
Notchy is a good word. I have a 99 Toy Avalon FWD w/95k miles. The rear wheel hubs do not have any play but they are definitely notchy. Off the car, it feels like the ball bearings have flat spots when you rotate by hand and you can hear it. They are hard to rotate but that could just be the right amount of preload. I've nver rotated a new assembly so I don't know what it should feel like. One of the hubs has been leaking grease. There is a wet spot on the bottom with the usual build-up of grime. Must be a bad seal.
I'm guessing at 95k I should replace both hubs. Agree?
Kestas
Staff member
New bearings are hard to turn. It took me a while to develop a decent feel for good vs bad bearings.
Some grease purge is normal. It's a judgement call whether you have too much grease purge.
Spalled bearings make noise long before there any discernible play in the bearing.
Do you get noise from the bearings while driving? How would you describe the noise?
Some grease purge is normal. It's a judgement call whether you have too much grease purge.
Spalled bearings make noise long before there any discernible play in the bearing.
Do you get noise from the bearings while driving? How would you describe the noise?
I haven't heard any noise but then my hearing isn't that great. When I turn the hub in my hand and hold it to my ear you can hear the bearings move. The sound is in sync with the notchy feel. If I hadn't removed the hubs to get to the strut mounting bolts, I would have not suspected I had a problem.
In doing some research, it seems like wheel hub bearing life on undriven wheels is 85-100k miles so I thought I would just replace them. OTOH, I have found over the years, that many new aftermarket parts are not as good as the used Toyota parts already on the car.
In doing some research, it seems like wheel hub bearing life on undriven wheels is 85-100k miles so I thought I would just replace them. OTOH, I have found over the years, that many new aftermarket parts are not as good as the used Toyota parts already on the car.
Got my SKF hubs today. They look great and operate 100% smooth compared to my old ones which feel a little notchy. Also, new ones turn with much drag than old ones.
So, what to do? My guess is that old ones will probably go many more 1000's of miles and why spend $225 if you don't need to? OTOH, it would give me peace of mind to have new hubs.
I know you can't tell me what to do from a distance, but I would appreciate any comments. The fact that there isn't any play or noise in my old hubs tells me I should run them for a few more years.
So, what to do? My guess is that old ones will probably go many more 1000's of miles and why spend $225 if you don't need to? OTOH, it would give me peace of mind to have new hubs.
I know you can't tell me what to do from a distance, but I would appreciate any comments. The fact that there isn't any play or noise in my old hubs tells me I should run them for a few more years.
Kestas
Staff member
Lack of drag on the old bearing may be an indication that the seals are not doing their job. For all the warranty parts I've seen with our product, the most prevalent cause for bearing failure is damage originating from water ingress past the seals.
I was hoping you would describe the noise as a humming or roaring noise coming from the rears, most noticeable at 30-50 mph. That's how most people describe it when I read the customer narratives.
You have no axle on the rear hubs, so anything you feel out of the ordinary when rotating the bearing is an indication of a compromised bearing. You should replace both bearings. Don't wait until there is play to replace the bearings. By then the damage is horribly advanced.
I was hoping you would describe the noise as a humming or roaring noise coming from the rears, most noticeable at 30-50 mph. That's how most people describe it when I read the customer narratives.
You have no axle on the rear hubs, so anything you feel out of the ordinary when rotating the bearing is an indication of a compromised bearing. You should replace both bearings. Don't wait until there is play to replace the bearings. By then the damage is horribly advanced.
Thanks Kestas. The new bearings have LESS drag than the old ones. But your points are still well taken by me. The fact that these guys have run almost 100k and feel a little rough suggests I should probably do something now.
Kestas
Staff member
For my curiosity, see if you can take the old bearings apart and look at the races. Also note the color of the grease.
Don't think there is any way to take it apart without destroying it. I did try to turn the ABS sproket but it would not budge. I think if I could remove the ABS sproket I could separate the hub but I will not do this unless I decide to install the new hubs. The original grease color was off-white. I could tell by the residual which was packed behind the inboard bearing. The grease between the bearings is a dark brown. When you rotate the hub (off the vehicle), you can observe the inboard ball bearing. The balls pick-up grease as they turn. I believe the races must be spalled because the ball bearings themselves look perfect.
One interesting note. SKF has a Technical Bulletin which says new hubs will often feel rough. It is because the grease has micro-crystals in it as required by many OEM customers. Once you start turning the hub, these crytals break down and the hub begins to turn smoothly. The new SKF hubs I purchased turn smoothly. I swear, there is a whole lot of technology in these wheel hubs!
One interesting note. SKF has a Technical Bulletin which says new hubs will often feel rough. It is because the grease has micro-crystals in it as required by many OEM customers. Once you start turning the hub, these crytals break down and the hub begins to turn smoothly. The new SKF hubs I purchased turn smoothly. I swear, there is a whole lot of technology in these wheel hubs!
Originally Posted By: artbuc
Notchy is a good word. I have a 99 Toy Avalon FWD w/95k miles. The rear wheel hubs do not have any play but they are definitely notchy. Off the car, it feels like the ball bearings have flat spots when you rotate by hand and you can hear it. They are hard to rotate but that could just be the right amount of preload. I've nver rotated a new assembly so I don't know what it should feel like. One of the hubs has been leaking grease. There is a wet spot on the bottom with the usual build-up of grime. Must be a bad seal.
I'm guessing at 95k I should replace both hubs. Agree?
Any time a sealed hub doesn't rotate smoothly, it should be replaced IMO. The resistance to turning can be surprisingly stiff (new bearings/seals) or can be VERY free (high mileage) but as long as it rotate SMOOTHLY, the resistance to turning isn't important.
Its also best to strip off the wheel, caliper, and rotor when assessing a bearing hub, too. I had a "bad bearing" grumble on the Cherokee a few weeks ago and the quick check of jacking it up , turning the wheel, and feeling for vibration in the coil spring didn't reveal anything unusual and the assembly seemed to be smooth-turning. The sound kept getting worse, though, so I pulled the wheel- but the caliper drag still masked any roughness. I then pulled off the caliper and I could *just* begin to feel something suspicious when I turned the rotor. Pulled the rotor- felt more roughness. When I finally had the hub off and disconnected from the front half-shaft spline, it was *very* clearly bad- as you said felt like the bearings all had flat spots.
Notchy is a good word. I have a 99 Toy Avalon FWD w/95k miles. The rear wheel hubs do not have any play but they are definitely notchy. Off the car, it feels like the ball bearings have flat spots when you rotate by hand and you can hear it. They are hard to rotate but that could just be the right amount of preload. I've nver rotated a new assembly so I don't know what it should feel like. One of the hubs has been leaking grease. There is a wet spot on the bottom with the usual build-up of grime. Must be a bad seal.
I'm guessing at 95k I should replace both hubs. Agree?
Any time a sealed hub doesn't rotate smoothly, it should be replaced IMO. The resistance to turning can be surprisingly stiff (new bearings/seals) or can be VERY free (high mileage) but as long as it rotate SMOOTHLY, the resistance to turning isn't important.
Its also best to strip off the wheel, caliper, and rotor when assessing a bearing hub, too. I had a "bad bearing" grumble on the Cherokee a few weeks ago and the quick check of jacking it up , turning the wheel, and feeling for vibration in the coil spring didn't reveal anything unusual and the assembly seemed to be smooth-turning. The sound kept getting worse, though, so I pulled the wheel- but the caliper drag still masked any roughness. I then pulled off the caliper and I could *just* begin to feel something suspicious when I turned the rotor. Pulled the rotor- felt more roughness. When I finally had the hub off and disconnected from the front half-shaft spline, it was *very* clearly bad- as you said felt like the bearings all had flat spots.
Kestas
Staff member
Originally Posted By: artbuc
One interesting note. SKF has a Technical Bulletin which says new hubs will often feel rough. It is because the grease has micro-crystals in it as required by many OEM customers. Once you start turning the hub, these crytals break down and the hub begins to turn smoothly...
That's one way to put a positive spin on a problem. Those microcrystals are from cheap grease that hasn't been milled sufficiently, leaving clinkers of thickener in the matrix. I never heard of a customer specifying microcrystals in their grease. If anything most labs have a way of checking grease for these spurious crystals.
It's not a serious problem, but I doubt they're paying a lot for that grease. Probaly bought it at TJ Maxx as an irregular grease. Gotta love aftermarket and their shortcuts.
One interesting note. SKF has a Technical Bulletin which says new hubs will often feel rough. It is because the grease has micro-crystals in it as required by many OEM customers. Once you start turning the hub, these crytals break down and the hub begins to turn smoothly...
That's one way to put a positive spin on a problem. Those microcrystals are from cheap grease that hasn't been milled sufficiently, leaving clinkers of thickener in the matrix. I never heard of a customer specifying microcrystals in their grease. If anything most labs have a way of checking grease for these spurious crystals.
It's not a serious problem, but I doubt they're paying a lot for that grease. Probaly bought it at TJ Maxx as an irregular grease. Gotta love aftermarket and their shortcuts.
Kestas, I spoke with SKF. They told me:
1. They only make one grade of wheel hub bearings. They used to make a "value grade" which they sourced from China. They had major quality issues and SKF terminated that program. Today they only make one quality grade. OEM = aftermarket.
2. A portion of their wheel hub manufacturing is outsourced. They would not tell what % is outsourced. They did not admit this, but I assume SKF outsources the manufacture of aftermarket hubs while they make OEM hubs at their own plants. They told me that all hubs (manufactured in-house and outsourded) are quality tested at the same USA lab and meet the same performance specs.
3. The hubs I have were manufactured in the USA by one of SKF's suppliers. It can be identified by the part # which is stamped on the outside edge of the outboard flange. Hubs manufactured directly by SKF do not have part numbers stamped on them.
Is any of this true based on your inside knowledge of SKF? Thanks.
1. They only make one grade of wheel hub bearings. They used to make a "value grade" which they sourced from China. They had major quality issues and SKF terminated that program. Today they only make one quality grade. OEM = aftermarket.
2. A portion of their wheel hub manufacturing is outsourced. They would not tell what % is outsourced. They did not admit this, but I assume SKF outsources the manufacture of aftermarket hubs while they make OEM hubs at their own plants. They told me that all hubs (manufactured in-house and outsourded) are quality tested at the same USA lab and meet the same performance specs.
3. The hubs I have were manufactured in the USA by one of SKF's suppliers. It can be identified by the part # which is stamped on the outside edge of the outboard flange. Hubs manufactured directly by SKF do not have part numbers stamped on them.
Is any of this true based on your inside knowledge of SKF? Thanks.
Kestas
Staff member
1. They are wrong. They market OEM and aftermarket, each has different performance criteria. They may have dropped what they called "value grade", but they are still marketing aftermarket hub bearings, and are working with China to source parts and hopefully source complete bearings. Because OEM is squeezing us dry with cost, performance, and warranty, our aftermarket program is booming profit-wise.
2. True. As with any manufacturer, many of the components are outsourced. For example, we have one bearing machined and assembled in the US from Korean forgings made from Japanese steel. Finding the percent foreign content of such product would be a nightmare, if not impossible. All automotive product (SKF-produced and outsourced) is tested in the lab I work at.
3. Hubs manufactured by SKF have numbers stamped on the flange edge.
I'm not an expert on the business dealing within our company. My expertise is more on the technical attributes of our product.
2. True. As with any manufacturer, many of the components are outsourced. For example, we have one bearing machined and assembled in the US from Korean forgings made from Japanese steel. Finding the percent foreign content of such product would be a nightmare, if not impossible. All automotive product (SKF-produced and outsourced) is tested in the lab I work at.
3. Hubs manufactured by SKF have numbers stamped on the flange edge.
I'm not an expert on the business dealing within our company. My expertise is more on the technical attributes of our product.
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