Last fall I installed new brake rotors on my car. With nearly 100K miles on it, the original rotors were fairly well rusted in place, making removal a challenge. Being the dumbass that I sometimes am, I forgot that I have a gear puller in my tool collection, and instead opted to beat the rotors loose with a hammer.
:smack:
The good news is that the new rotors are flat and true, giving me nice smooth braking. The bad news is that my hammer antics appear to have brinelled one or more of the bearings. Although the running noise isn’t really bad, I’d like to replace the damaged bearings this spring - however, I don’t want to replace all four unless all four are damaged. The puzzle, then, is how do I identify which bearings are bad? They don’t make noise unless the car is rolling down the road, which in turn makes it hard to listen to each individual wheel.
I’m not terribly bothered by the cost; as you note, bearings are relatively cheap. It’s my time that I don’t want to waste (why oh why didn’t I go look for the damn bearing puller… :smack: ). I figure each bearing will probably take me at least an hour and a half to swap out.
If you listen to the bearing with a stethoscope, you can more closely tell if there is anything wrong with it. A long screwdriver makes a perfectly good stethoscope. If you could jack up the car so that all four wheels are off the ground, you could listen to each one and compare.
Bearings may be cheap, but a man’s time cost dearly.
My usual method (I’m preparing for a deluge of safety-related complaints for saying this) is to jack up one corner, wheels chocked and axle stand under chassis, then run the one wheel up to about 60mph, by which point a bad bearing will be making a rumbling noise. If no noise, and no play on the wheel (always a good idea to give it a push and a pull while it’s in the air to check for play in ball joints) then the bearing is declared OK.
None driven axles can be checked by turning the wheel by hand, it’s motion should feel smooth, not rough, and should keep spinning after you give it a push around, although if the brakes are dragging then it may be hard to distinguish from a bearing on it’s way out.
The wobbling the wheel method is only really useful for telling a bearing that is knackered, not merely worn. I’ve had bearings run noisy for over a thousand miles without being able to feel play at the wheel.
If you don’t fancy spinning your car wheels in the air (and I’m not advocating it, there certainly is some element of danger which is reduced somewhat by making sure the wheels are properly chocked and the car isn’t just sitting on a jack, but I’m simply stating what I do, not telling you to do it.) then you can often get a pretty good idea by listening carefully while cornering at speed. Not so fast that you’re near the limits of grip, but enough to transfer weight to the outside wheels. When a bad wheel bearing gets extra load on it, it gets louder. By paying attention to which direction makes the most noise, you can at least know which side of the car to look at, although in this particular case where all four are suspect, maybe not so useful.
I have never seen a gear puller used to remove a stuck brake rotor. How big is this puller?
I have oxy/Act torch set and also a bottle of “never Seeze” that I use on almost everything I work on.
As for wheel bearings being cheap? So many now are assembles and can cost more than $150.00 each.
If that is still cheap, what are you doing driving a car with 100K on it?
I just had a bad bearing replaced. Drive down the road slowly and stear left and right. That will take weight off that side of the car and reduce or eliminate the noise.
and, if possible, go with the OE part and not an aftermarket replacement. I had a parts-store brand wheel bearing on my car only last about 15,000 miles.
Won’t be an issue; I’m expecting to sell the car later this year.
Don’t recall. You’re right, it may not work, but I probably could have rigged something to preload the rotors so that a very gentle tap from a hammer would have been enough to get them loose. I’m expecting the ones I just installed should come off very easily when I go to replace the bearings, so this may not be an issue going forward.
With the wheel off the ground, put one hand on the coil spring, or strut, or something attached to the part that houses the bearing. Rotate the wheel with the other hand (tranny in neutral for the drive wheels). You’ll be able to feel a vibration through your fingers, rather like a hum, from any wheel whose bearing isn’t running smoothly. This will detect a faulty bearing long before it gets bad enough to have an obvious rumble or discernable play.
Turning side-to-side does not give a definitive answer. That technique worked well with older cars that had separate tapered roller bearings, but is not reliable (and is thus useless for the problem at hand) on modern designs with one-piece double ball bearings. The noise can be from either the loaded side’s outer bearing OR the unloaded side’s inner bearing.
Again, with separate tapered roller bearings, yes, it’s wise to replace both the inner and outer bearings on one side. With one-piece double bearings, there’s no need to replace both bearings on a given axle. The bearing at one wheel is already a “pair,” having both an inner and an outer bearing integrated into it.
Bearings can be bad with “zero wiggle”. I went round and round with my mechanic on this. I had an annoying woWOWowoWOWow noise coming from my right rear wheel. I told my mechanic to check the bearing, and he said there was no play in it, so it wasn’t the bearing. I replaced the tires, and it wasn’t tire noise. He did the brakes, it wasn’t the brakes.
Finally, I told him to replace the bearing. The noise stopped. Coincidence?
Yes. See Brinelling. This is what hammer blows do to a bearing. The noise isn’t very loud, so we’re not talking about massive divots in the races and flat spots on the balls/rollers.
True, but it’s definately a quick check to tell if the bearing is shot, especially on an older style tapered bearing. I don’t like the “turn the wheel by hand and feel for drag/noise” method. As someone else said it could be the brakes dragging …etc. I had a bearing go bad recently on my Honda CR V. Man, that puppy was LOUD. No mistaking which one was bad, but I could definately hear the bearing “load up” on a sharp turn! I had a mechanic do it (had zero time to do it myself) and it cost me 260$. If I bought the bearing myself it would have cost me 50$. Bearings ain’t so cheap anymore.
Sometimes I wrestle with when I should avoid being too picky about correcting things that aren’t quite accurate, and when I should rectify things that might give readers a false impression. In this case, let me sum up as follows:
If a modern one-piece double bearing has any play, it’s faulty. However, it can be faulty without exhibiting play.
If it clearly sounds or feels rough when turning the wheel by hand, it’s faulty, but again it can be faulty without being detectable this way.
A stethoscope can be useful in finding a rough bearing, but generally only if the bearing is spinning at some speed. This usually means with the engine running and the tranny in gear to turn the wheels. Unfortunately, that condition introduces other noises in the engine and drivetrain which sometimes makes it hard to be absolutely certain that one is hearing bearing noise instead of something else.
Turning side-to-side and noting in which direction the noise is present will not dependably identify which side of the vehicle has the faulty bearing.
I have found the method I described (turning by hand with fingertips on the spring to feel for vibration) to be the most helpful for identifying a bad bearing. It’s essentially using the relevant suspension component as a giant stethoscope, and using fingers instead of ears to detect the roughness.
I have only seen worn hubs in situations where there was significant play in the bearing.
