Im trying to figure out the road noise that occurs when going over 40mph. Made sure my tires were inflated to proper psi, problem persisted. The noise is almost a hum, not very loud - at first thought it was just the way the car sounded. But it has gotten a little worse, which tells me that there is something not right. Responses in prior posts suggested bad bearings or stuck caliper.

So this weekend I jacked the car up, and the front right tire spins, and will spin a little after I "stop spinning" it.

The right tire spins ok, but right when I let go of it, the wheel stops.

Does this indicate a problem, or is this normal operation?

How would I diagnose the difference between bad wheel bearings and a stuck caliper?

Thanks!!!

Oh btw the car is an 82 240d

If its a dragging caliper you should be able to feel the rim getting hot after a drive. Or you would see the brake pads on one caliper wearing more.

Its probably a bad wheel bearing, grab the wheel and see if it has any side to side, or up and down play. When wheel bearings start to go you get some slop.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

they wont spin freely unless you push the pads away from the rotor.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Yup.

Though oddly enough, my friend's 78 Nova with front disc brakes would spin freely for quite some time. It's one of those calipers with one gigantic piston, maybe that has something to do with it.

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1985 CA 300D Turbo , 213K mi

How long a wheel spins has probably nothing to do with a hum at 40 mph. Is the noise the same on different types of pavement? is the noise different if the car is put in neutral at 40 or does it lessen? is the noise different if you lift off the throttle slightly? Does the noise always occur at the same road speed or the same engine RPM? By that I mean, have you put it in say second gear at 40 to see if its better or worse. Have you swapped front tires to rear to see if problem changes? These diagnostics need to be done for us to help. Could be as simple as a cupped tire tread.

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81 300CD (sold) 1972 280 SEL 4.5 (sold) 1966 250 S 4 spd (sold) 1974 450 SL (sold) 86 BMW 325ES (sold), 1973 280C (sold) 1988 300 SE.

To answer your questions carnut:

The tires are fairly new, and like I stated earlier they are properly inflated - however even with fairly new tires, I understand that there can be issues. I have the warranty from discount, ill get a rotation and see if that helps at all.

As far as other troubleshooting, it sounds the same on all pavement (concrete and asphalt). The nose is there if I have the clutch in, or if its in neutral. No change - so I know it has nothing to do with the tranny. I could be going say 60 on the freeway, push in the clutch or put it in neutral, and the noise sounds exactly the same. Best way to describe the noise is very low psi on the tire, or driving down the freeway with the door open/window open. Not a bad noise, but excessive road noise.

Thanks!

That is what my bearing on the left side sounded like. There was no play, but it did "clock" like a model type electric motor with magnets when you turned it by hand. I replaced bearing and races on both sides.

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RRGrassi


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