Weird grinding sound from back left wheel
 

I was driving home my 240D last night and noticed a weird grinding now that occurred every time my back left wheel made a rotation. It almost sounded like metal of metal. I had this same thing occur about two months ago and just sprayed a bunch of liquid wrench up in there and it went away. Should I just do that again or is this something else that needs to be fixed ASAP?

Check the rear sway bar link on that side.

Is this a critical thing that needs replacing or can I just shoot some more liquid wrench up there? I just put money into the car and I'm tapped out.

Sway bar links usually rattle or clunk and is usually caused by bumps. I would suspect a wheel related problem.

It could be really dangerous if it's worn or broken brake parts. And it's really not a good idea to hose down your brakes with anything other than brake cleaner. Greasy/oily brake pads are not safe. Troubleshooting is free, I highly suggest you take a few minutes to troubleshoot to see if you can figure out what it is.

Jack the car up, and spin the wheel by hand, and see if you can hear or feel anything. Try wiggling the wheel with you hands at 12 and 6, and then at 3 and 9 on the proverbial wheel clock. See if you hear any grinding or can feel any wiggle. Then I'd pull the wheel and give everything a once over. Check the obvious first. Make sure your pad aren't worn too low. I've had rocks get stuck in the calipers and cause grinding/squealing noise. Might even take the pads out just to make sure nothing is binding. You could have also bent the dust shield making it rub.

Also if you post your location you might find a local Forum Member that can make a stop by and help troubleshoot.

If that is what it is. It would be the easiest thing to diagnose and least expensive fix you could hope for.

Where exactly where you spraying the lubricant? It is most likely that is where the bad part is. There are more than one on a back wheel assembly.

All over the place. I didn't really discriminate with my spraying since the last time it happened I was hours from home. It got rid of it for a couple months though.

Okay then a physical inspection is a good ideal. It is probable and hopeful that it is something cheap. If something lets go and you have to employ a towtruck for example. Your would still be faced with fixing whatever caused the need for a towtruck.

This could really increase the cost. Remember it could be something minor. Never a particular good ideal to randomly spray stuff up there as the brake can become contaminated.

if the noise is present at all times the wheel is moving, it's TOTALLY CRITICAL you lift and secure the vehicle, and remove the offending wheel, and find the noise.
if it's bearing related, the wheel can fall off. it can even catch fire (yes, brake fluid IS flammable) if you've never seen what a wheel falling off a car can damage... you don't want to on your own car!
if you have wheel chocks, and a jack, and a lug wrench, you can easily pull the parts off and look to see what's wrong.

Curious what this turns out to be. My top guesses are:

- Worn-out brake pads
- Rock caught in caliper
- Dragging parking brake shoe
- Dust shield rubbing on the rotor.

I sprayed some liquid wrench around where the wheel turns and it went away.

Sooo the noise went away, and now it is all fixed???:confused:

I think you need to go back and start at post #2 and reread everything.:cool:

I don`t know where you live, but there has been several times in the past where there has been posted pictures of a Trailing Arm about ready to break in two form rust damage.

Get under there and check things out. now it can be something simple and no Biggie, and it can be a life threating failure.

Charlie

THIS!

AND THIS!

It is somewhat likely you are experiencing a wheel bearing failure. At least jack it up and try the wheel wiggle test. If it wiggles, you need bearings.

I jacked it up and zero play in the wheel. It ended up going away and hasn't resurfaced. As long as there's no play it should be fine right?

One of our Members; think it was Stretch (a.k.a Army) had a noisy rear Hub bearing and he drilled and tapped the Trailing Arm Bearing Carrier for a Grease Zerke and pumped it with Grease and the sound went away.

Apparently the Old Grease was not lubing properly??? Maybe dried out???

I think no end play just means it is not worn enough have end play you can feel.

What did you get on the Dial Indicator?