wheel bearings

No, but they do give signs indicating that they need replacement.

You don't mention model and year. The old tapered rollers should be cleaned and repacked regularly; I do mine every time I change the brake pads. If they're the new style sealed bearings they don't require any service.

If they're rumbling, clicking, snapping etc they need replacing, regardless of which style you have. Be sure that's your problem though; other problems can cause similar noises.

Depending on the type of wheel bearing, they may make noise but there usually is no visual sign unless you remove the bearings and inspect them.

Thanks. Is there anyway to test if they need to be cleaned/repacked?

t again, paul

Wheel bearings are generally cleaned and repacked according to a time and mileage schedule because there is no real way to test, other than removing them, cleaning them, and visually inspecting them. If they are making noise or have excessive freeplay, then they need replacement.

Not all wheel bearings are designed to be cleaned and repacked. Most front wheel drive vehicles have sealed maintenance-free bearings.

========================== I have the sealed front wheel bearings - got to be typical of many FWD Toyota - manual says the preload is set by the axle nut torque. The factory service manual shows a specification for axial play - IIRC .001". When I mounted a dial indicator to check runout in the disc rotor I also checked the wheel bearings for play - both were fine. If the wheel bearings do require replacement they need to be pressed out and in as a sealed unit. I detected zero play at 150,000 miles so hopefully, they'll continue to perform well. This is kind of a nice testament to Toyota design. With the old style wheel bearings using a castellated nut, you would tighten (snug not over tight) and then back off one position, but the resulting free play was never zero. I understand the typcial wheel bearing road test is to turn side to side and see if noise changes with varying load placed on the wheel. Once had a rear wheel bearing go in an American full size rear wheel drive car and the symptom was a growling noise.

... as well as more modern 4wd and 4runner trucks after about 95 I believe. 2WD trucks (rear wheel drive) continue to use the old style tapered roller bearings at least through 2004 model year.

As I posted earlier, posting your year and model Toyota would be of some help.

New style - nothing to do but replace if needed. No service is required.

Old style - If you have them apart as part of a brake job you might as well clean and repack them. If you've been driving in water above the level of the hubs you should inspect for water infiltration and clean and repack if needed.

I do get a very high pitched squeal when turning the wheel almost fully at low speeds. I have heard this on other cars frequently and never associated it with wheel bearings, but I do not know what causes it.

My service manual calls for repack every 2 years or 24 k miles which is ridicules. And it does require special tools.

I see. It's a pity you hadn't posted that to begin with. Of course, we're still waiting for you to provide year and model but despite this I'm prepared to make a diagnosis of your "problem."

A high pitched whine is a normal sound made by the power steering pump under these conditions. At low speeds when the power steering system is inder the most load, or at full steering wheel lock, it can be quite loud but is still perfectly normal. What may not be normal is a bloodcurdling squeal caused by a slipping power steering pump belt under the same conditions; this however is unmistakable and very, very loud. In any case I have no idea why you'd think this is a wheel bearing sound.

May I ask why you consider two years or 24K miles "ridicules" (sic)? Either the grease needs to be replaced due to use, or it needs to be replaced due to condensation in the hub from lack of use.

Oh, never mind. Just remind me never to let you work on my car.

-- Mike Harris Austin TX

"Just remind me never to let you work on my car." OK, I have too many others to do.

1-I have done all maintenance of every car/pickup I have owned in the last 29 years and have never had a maintenance related failure. I have done most repairs on my cars/pickups for the last 29 years and have never had a repair related failure. I have done the same for many of my friends vehicles.

"May I ask why you consider two years or 24K miles "ridicules" (sic)? Either the grease needs to be replaced due to use", or it needs to be replaced due to condensation in the hub from lack of use."

2-I have never had a car/pickup that called for anywhere near this frequency of clean/repacking of wheel bearings.

2a-My vehicle had 17k miles on it at the two year point. It is used everyday and never runs for under 20 minutes, and usually longer. The wheels are never submerged. Not exposed to sea salt or harsh road conditions.

Your reply: "I have no idea why you'd think this is a wheel bearing sound." To my comment: "I have heard this on other cars frequently and never associated it with wheel bearings" So why do you say that I make this association?

"Of course, we're still waiting for you to provide year and model" I wanted general advice not based on make/model/year.

2003 toyota tecoma. Never towed anything. Ambient 35 to 105°F. Frequency of carrying something in the bed over 50 lbs is once or twice a year. Max ever carried in the bed is 500 lbs.

additional points. There are three levels of maintenance on this vehicle and all three call for the same wheel bearing maintenance. Service schedule calls for the wheel bearings to be "lubricated". The dealer service dept "told" me that this means clean/repack.

It is difficult to diagnose a sound without actually hearing the sound, but if you a continuous squeal/screech sound when the steering wheel is turned all the way to the limit is probably the power steering pump or accessory drive belt. I assume you know this, but just in case you do not, it is not a good practice to hold the steering wheel against the stops on a vehicle with power steering. Check accessory drive belt tension and belt condition to make sure it is not glazed. A squeak/crunch sound when the steering wheel is turned all or most of the way to the limit can be the stopper rubbing against the stops. The stopper comes with a plastic cover that sometimes gets broken off if the wheel hits a bump while the stopper is against the stops, and then instead of plastic-to-metal contact, you get metal-to metal contact that sounds like amplified nails on a blackboard when going over a bump.

As I mentioned before, you need to visually inspect wheel bearings to determine whether they are discolored or pitted or need replacement. A bad wheel bearing can make all kinds of different noises, from whining to rumbling to rubbing. Generally, the sound from a bad wheel bearing will sound rotational and the frequency, pitch, and/or amplitude will increase with wheel speed, and the sound may change in pitch and/or frequency when turning. Wheel bearing sounds are usually less apparent at low speeds than at higher speeds.

Regarding the frequency of wheel bearing re-packing, that depends on the type of wheel bearing and the vehicle application. For your use, I would service the bearings according to mileage rather than time, which would cut down on the frequency a little bit. If you do the work yourself, Snap-On makes a very nice wheel bearing packer that pushes out the old grease with new grease, making that part of the job a 30 second process.

jumping in in the middle, i also feel a repack, etc. at 24K is a bit often. i can see poking it with a grease gun, etc but..... of course, i consider 17K miles in 2 years nearly parked.

my echo did have a wheel bearing get noisy at about 105K and although i'm pretty well into cars since the forties, it didn't sound like the usual/normal noise. when it began getting loose i finally changed it and it WAS bad. you're right, many people don't recognize the belt slippage. sammm

Another FWIW data point: a Volvo 440 I once had made a shrilling noise when I turned the wheel in one direction. It proved to be a stone that had got lodged next to one of the disk brakes. (By chance, that was on the way home from having it serviced, when I chose to take a scenic back route on a hot dry day when the road rubbish was free to fly up.) Removing the stone fixed things.

might say you got your rocks off? sammmm

In a hmm-manner of speaking... Out, at least.