Odd Metallic Noise coming from Front Left Wheel well......hubs?

[Aggmeister2010]

Hi everyone,

I'm trying to diagnose a noise that's driving me nuts. It seems to be coming from something in the front left wheel well of my P90D. Here's a sample of the noise:

https://imgur.com/a/AY2LDtu

The noise sounds like a metallic rattle/scrape (I thought it was the air strut at first). It is heard when going over bumps only. I can only hear it with the windows down. But form outside, it's loud.

What I've discovered in hunting it down so far:

• It's not the air shock...I replaced that with a spare unit, no change in the noise at all.
• All of the bushings/joints in the control arms seem to be in good shape.
• When I tap the spindle or brake rotor with a rubber mallet, I hear the same noise.

The only thing I can think of is maybe the hub is failing in a weird way? Normally a failing wheel bearing is a hum or whine, not a sharp noise over bumps...but I don't have any looseness in the wheel or hums that I'd expect from a bad bearing.

Any thoughts?

 

[Gtech]

Hi everyone,

I'm trying to diagnose a noise that's driving me nuts. It seems to be coming from something in the front left wheel well of my P90D. Here's a sample of the noise:

https://imgur.com/a/AY2LDtu

The noise sounds like a metallic rattle/scrape (I thought it was the air strut at first). It is heard when going over bumps only. I can only hear it with the windows down. But form outside, it's loud.

What I've discovered in hunting it down so far:

• It's not the air shock...I replaced that with a spare unit, no change in the noise at all.
• All of the bushings/joints in the control arms seem to be in good shape.
• When I tap the spindle or brake rotor with a rubber mallet, I hear the same noise.

The only thing I can think of is maybe the hub is failing in a weird way? Normally a failing wheel bearing is a hum or whine, not a sharp noise over bumps...but I don't have any looseness in the wheel or hums that I'd expect from a bad bearing.

Any thoughts?

Could be a broken spring/clip from your caliper (nr8) not sure how you call it. Did you unscrew the caliper and did the mallet test also?

 

[Aggmeister2010]

Could be a broken spring/clip from your caliper (nr8) not sure how you call it. Did you unscrew the caliper and did the mallet test also?

that’s a very good point. I didn’t check that, I will look at it today.

 

[Doanster1]

Def check the spring clip first, but I had pretty much the same rattling only when going over cobblestone type roads, ie continuously uneven patches. Ended up being the wheel bearings so you def have a keen troubleshooting sense.
Did you zip tie a GoPro to the A-arm???

 

[Aggmeister2010]

Def check the spring clip first, but I had pretty much the same rattling only when going over cobblestone type roads, ie continuously uneven patches. Ended up being the wheel bearings so you def have a keen troubleshooting sense.
Did you zip tie a GoPro to the A-arm???

Interesting. I'm still baffled as to what inside the bearing could be causing that noise, but at least i might know how to eliminate it. Fortunately good quality replacements are available on RockAuto!

Actually, it's worse than GoPro on the A-Arm...........it's iPhone 12 duct taped to the upper air strut mount area. Redneck engineering.

 

[David.85D]

It seems to happen when the suspension is moving. I’d start with sway bar end links, ball joints.
Your tapping test makes me think it’s a loose dust shield bouncing around…

Seems too low pitched to be a bearing. I’ve had one go bad on my MS and it was much higher pitch.

 

[Aggmeister2010]

It seems to happen when the suspension is moving. I’d start with sway bar end links, ball joints.
Your tapping test makes me think it’s a loose dust shield bouncing around…

Seems too low pitched to be a bearing. I’ve had one go bad on my MS and it was much higher pitch.

I've checked all of the regular offenders - end links are in good shape, ball joints are fine, no stretching of the fore-arms, all dust shields were removed.....

The mallet test showed me that the noise is coming somewhere from something spindle/knuckle/hub/brake related. Knocking on those is what gives me a similar noise.

 

[David.85D]

You are doing all the right things. I’d unbolt the caliper and move it out of contact and then do your knock test again. That ought to narrow it down.

have you checked the torque on the axle nut?

 

[Aggmeister2010]

You are doing all the right things. I’d unbolt the caliper and move it out of contact and then do your knock test again. That ought to narrow it down.

have you checked the torque on the axle nut?

I did put pressure on the caliper retaining clip when i was doing my knock test and didnt notice a difference in sound, but you're right I need to take the whole thing off to totally rule it out.

I haven't checked the axle nut torque, good point. I went ahead and ordered a replacement hub from RockAuto since they're not that expensive and pretty easy to replace...you have to take the caliper off to replace it anyway, so i'll do the knock test again then and see what happens.

 

[Doanster1]

Axle nut better NOT be loose. That thing just doesn’t come loose on its own.

 

[David.85D]

Axle nut better NOT be loose. That thing just doesn’t come loose on its own.

I would like to think this is true, but it’s a known issue with axle creaking. Greasing the splines and retorqueing the nut is the official fix. Thought it was worth a check here since it’s been tricky

 

[Doanster1]

I would like to think this is true, but it’s a known issue with axle creaking. Greasing the splines and retorqueing the nut is the official fix. Thought it was worth a check here since it’s been tricky

Absolutely worth the check. Didn’t mean to suggest otherwise. Tongue’n’cheek that you have bigger probs if the axle nut was loose, so to speak.

 

[dark cloud]

Absolutely worth the check. Didn’t mean to suggest otherwise. Tongue’n’cheek that you have bigger probs if the axle nut was loose, so to speak.

I have read here more than once that some have found the axles nuts not necessarily loose, but not torqued to the spec. Looks like it was an actual service bulletin for 2012 years to install a locking washer. Of course this was before front motors, so on the rear only, as the bulletin claims due to heavy acceleration. Not sure if other years found the similar issue or not, or if it applied to the front hubs as well?

https://static.nhtsa.gov/odi/tsbs/2013/SB-10051603-7158.pdf

 

[Aggmeister2010]

!! SOLVED !!

It was the wheel Hub! Today I pulled the original hub off and replaced it. You could actually hear the bearings rattling around inside when you shake it.

The Noise in the video is completely gone. I suspect my LR hub will need replacing eventually as well, so perhaps I'll just do all 4. My car only has 40k miles, so this is a depressing prognosis, but whatever. Not very difficult work, at least.

FYI, since I couldn't find it posted anywhere, the axle nut is a 32MM, and needs to be torqued to 205 NM.

Hub puller and torque wrench are required, and are rentable from any major auto parts store. Go with the "claw" style hub puller if you can, the standard one is poorly cast and doesnt quite fit around the lug nuts...had to shave mine down.

By the way, It seems like the SKF BR931008 from RockAuto *is* the OEM, so save some money and buy that.

 

[David.85D]

By the way, It seems like the SKF BR931008 from RockAuto *is* the OEM, so save some money and buy that.

This is good news. SKF are good bearings

 

[Doanster1]

32mm socket not in my bag of tools so good to know should I need to replace the hubs again. Nice job!

 

[David.85D]

FYI. This is the entry on that SKF wheel hub - they list it as compatible with many Model S and Model X, and with OE number 102717000A

SKF