Grinding noise coming from rear driver's side

[Viper Driver]

Okay, I'm really not sure what this noise is, so I'm going to put it to you guys to see if someone can help me out.

I was driving this weekend and noticed a squeaking/grinding noise coming from the left rear wheel whenever I'd slow down to a stop, sounding close to the noise you get when the thin metal clips scrape on the rotor when your brake pads are worn out. So, I jacked the NSX up and found that the brake pads were less than 50% worn out! I couldn't figure it out.

So, I cleaned everything out and reinstalled the caliper, then I ran the car while it was in the air to see if I could diagnose the noise. No noise at all. I got in the car and went for a drive. Everything was fine for about ten minutes, then the noise started up again. The longer I drove, the worse it got. I could hear something scraping as I drove down the road and then something from the rear driver's side wheel would make all kinds of noises as I'd come to a stop. It's not super loud, but it's definitely noticeable. It's not a sound like brake pads rubbing (ie., a stuck caliper). It's definitely something metal scraping on something else. It's really loud and annoying at really slow speeds, particularly when starting/stopping.

So, I get home, scraping all the way into the garage, and immediately jacked the car up. No noise at all! I apply the brakes with the wheels spinning, and I still can't re-create the noise I hear when I'm driving. Obviously, it's not making the noise when the car is in the air.

Other things to add-

A month ago, I put a set of TEIN coilovers on the car, dropping it about 3/4 of an inch over my Eibachs.
2 weeks ago, I changed the springs out on my rear TEIN coilovers.
On Friday, I had a 4-wheel alignment done on the car.
Other than that, nothing has been done to the brakes/suspension in some time.

Anybody have any ideas as to what this could be?

 

[NSX-Racer]

If you hear a change in that noise during cornering it may be a bad wheel bearing. That noise can change with different vertical and lateral load.

 

[DanO]

When you have your car jacked up, grab the wheel in question at the 6 o-clock and 12 o-clock position and see if there is any play in the wheel bearing by trying to wiggle the wheel back and forth. If it has some play, then it could be a wheel bearing.

HTH,
DanO

 

[NSX-Racer]

Dan: as you may know a wheel bearing can even be bad when you don't have a play. I had that case a long time ago when even specialists from Honda Germany didn't realize that a rear wheel bearing was bad. They changed the whole tranny for free (at less than 30,000 km!) because they thought the noise comes from the tranny. False diagnosis.

 

[DanO]

They changed the whole tranny for free (at less than 30,000 km!) because they thought the noise comes from the tranny. False diagnosis.

Good point!

That's funny because our local Honda dealer just did the exact same thing to my mother's new Accord. False diagnosis.

DanO

 

[prova4re]

Does it make that squeaking sound when the car is rotating?
Is it worse when you hit a few bumps?

Check your dust shields, to make sure there is not a rock jamed in there.
And they are not rubbing on your rotor.

I would also check your Teins, the top nut has to be tight.
Some times when you drive they come lose, try grabing the top of the shock with a wrench on the flat part.
Then tighten the nut down, if it moves just a little this will make a big difference.

 

[nsxtasy]

From the "don't overlook the easy things first" school... Is it possible that the inside brake pad is worn down to the squeaker tab, even though the outside one isn't that worn?

 

[Viper Driver]

Does it make that squeaking sound when the car is rotating?

Yes, only when the car is rolling and it doesn't make the sound at all when the rear tires are in the air (car is jacked up)

Is it worse when you hit a few bumps?

Nope. It sounds like it gets worse when the car is going slower, and the scraping noise has a cyclic sound that corresponds to the rotation of the wheel.

Check your dust shields, to make sure there is not a rock jamed in there.
And they are not rubbing on your rotor.

I just got back from the Acura dealer and had our NSX Tech look at it. One of the first things he checked was the dust shield to make sure it wasn't rubbing on the rotor.

Let me be clear here.....the car does not make a sound until after about five minutes of driving. After that, the noise begins. Sometimes, the sound level will change or stop completely by tapping on the accelerator or brake.

I would also check your Teins, the top nut has to be tight.
Some times when you drive they come lose, try grabing the top of the shock with a wrench on the flat part.
Then tighten the nut down, if it moves just a little this will make a big difference.

I'll check it, but I don't think that this is the source of the noise due to the fact that the sound corresponds to wheelspin and not bumps/suspension movement.

Ken, I did remove the brake pads and inspected them because initially I thought that the noise was the metal clips scraping on the rotor due to them being worn out. The pads look fine to me.

After talking to the NSX Tech and letting him listen to the noise, he told me that it may be the axle nut/driveshaft might be loose and the new suspension angles are highlighting the problem. I'm going to get in there and back the nut off slightly, spray some penetrating oil in the bearing area, and re-tighten. If the sound goes away, then my problem is solved. If not, then he says it's probably time for a new bearing. $$

Thanks to everyone for helping me!

 

[nsxtasy]

he told me that it may be the axle nut/driveshaft might be loose and the new suspension angles are highlighting the problem. I'm going to get in there and back the nut off slightly, spray some penetrating oil in the bearing area, and re-tighten.

You can read more about the axle nut (and how to tell whether it has backed out) in this previous topic.

Before doing anything with it, make sure you have a torque wrench that measures high enough; it's a pretty high torque setting, as I recall.

 

[Ether]

I had very similar symptoms about a year ago, also coming from the left rear wheel. Although I would describe the sound as clunking rather than grinding.

Turned out to be a bad wheel bearing, parts and labor were $460.00

 

[DanO]

I'm going to get in there and back the nut off slightly, spray some penetrating oil in the bearing area, and re-tighten.

Ok, go for it, but I’m not sure what spraying penetrating oil at the spindle will accomplish?

You’ll need a 36mm socket and a HUGE breaker bar or a ¾” impact gun to remove the axle nut. If the nut comes off easily then it might have been a little too loose and so the bearing would be already shot. You’ll need a new axle nut and a torque wrench capable of 270 lb-ft to install. Don’t forget to “double-stake” the nut the way that John Vasos recommends (see above NSXTACY link)

The bearing is pressed into the hub assembly, so you do not need to replace both—just the bearing--this should save you some cash. Any shop should be able to remove the bearing from the hub assembly and press the new one in for you. Or, you might be able to do it yourself with a vice and an improvised spacer.

Good luck and keep us up to date!

DanO

 

[ajnsx]

if all this fails check for that little creature that was on the airplane wing from the twilight zone movie!

 

[jeff_L]

maybe a stuck brake piston? is the noise there when the brakes are applied, or only when coasting?

jeff

 

[MJK]

It sounds like it is heat related to me due to the time needed for it to manifest. Going on the assumption that a braking issue is going to be cheaper to fix than a bad bearing, I'd check that first.

Does it make the same noise if you slow down with the brakes as it does it you just coast to a stop? Play with the e-brake too. If you can vary the sound by screwing with either the brakes or e-brake I would focus my energy there. What pads are you running?

If its not in the brake system, I think you are on the money with the wheel bearing diagnosis.

 

[Viper Driver]

An update:

Spencer (NSXT) and I took the car out for a drive on Saturday, and I was able to show him the noise as well. He was just as confused as I was, so we took it back to my house and jacked it up. After a bit of disassembly, we prepared to remove the axle nut. It came off WAY too easily, which sent off some warning flags in Spencer's mind. Sure enough, after taking the hub assembly off, it was pretty clear that the bearing was shot. The strange thing was that it wasn't making the same noise that other bearings make when they go bad.

Anyways, thanks for all of the help! I have a new bearing on order and I'll have one of our local race shops press in the new one when it gets here.

 

[nsxtasy]

Did you happen to notice whether you could tell the axle nut was loose from the stake mark moving, as noted here?

I'm just wondering whether a loose axle nut (which is easy to detect from looking at it) might indicate that there's a problem before it gets bad enough to hear the grinding sound. Or whether the loose axle nut happens before it gets bad enough for the bearing to go, so you can prevent it...? (Just guessing here - tech gurus, help me out!)

 

[Viper Driver]

Ken-

Whoever put on the axle nut had not "notched" it correctly, and there was a thin v-shaped notch instead of a wide, flat one to secure the nut in one position. The nut had probably loosened about 1/32" of a turn and the v-shaped notch was on the "loose" side of the groove. I don't know if this is enough to cause any premature wear on the bearing, though.

Judging from the condition of the bearing, it had probably been going bad for some time and the recent alignment had put it into a position to make itself known audibly. Funny, but the car has passed many recent tech inspections and (before we removed the hub) it felt pretty good to Spencer and I. The alarming thing was how quickly the sound finally mainfested itself and how bad the condition the bearing was in before this happened. It almost makes me want to go out and buy one of those big ol' torque wrenches ($$) so I can check it periodically.

Chuck

 

[NSX-Racer]

Is it okay to be a bit proud of bringing up the right diagnosis first??

 

[nsxtasy]

Whoever put on the axle nut had not "notched" it correctly, and there was a thin v-shaped notch instead of a wide, flat one to secure the nut in one position.

That's very common.

The nut had probably loosened about 1/32" of a turn and the v-shaped notch was on the "loose" side of the groove.

When it's loose, it can be loose even a little bit, like that. The good news is, it's easily observable... but only if you're looking for it.

It almost makes me want to go out and buy one of those big ol' torque wrenches ($$) so I can check it periodically.

I think you can check it just by observing, as long as it has been properly staked. Even a single V in the middle of the notch is enough, if you keep an eye on it.

Incidentally, if you DO get a torque wrench for the axle nut, remember that it needs a very high torque setting, so make sure you get one that reads that high. And you may need a breaker bar or a piece of pipe for it as well.

Is it okay to be a bit proud of bringing up the right diagnosis first??

Yes. Good job.

 

[NSXT]

As I saw the stake mark, it looked to me as though it was on the tighter side of axle cutout, not the looser. In either case, the nut should not have moved enough to cause premature failure.

ViperDrivers bearing has about 1/10 inch of axial play, where the spec is 0.002 inch. The reason why we didn't detect this immediately was that the brake rotor/pads/caliper assembly was holding the hub in place.

While I didn't have a torque wrench, I can say thay it didn't take much more than lug nut effort to remove the axle nut. Assuming that the mean little robot which assembled this 242lb-ft nut was operating properly, something weird has happened to allow the nut to come off so easily.

I have a few theories, but I hope to do some measurements and dissection as the old bearing gets replaced, as I would really like to understand why this bearing failed so soon.

 

[Viper Driver]

Cross-posting more on this story here........

http://www.nsxprime.com/forums/showthread.php?s=&postid=290776#post290776

 

[Dan Ciezniewzki]

i've been having the same problem with my 01 nsx that i bought in sept with 6500 miles on it and noticed it around 7000 to the present 9400. I got it from an acura dealer with the warenty, do you guys think the warenty would cover this?

At first I thought it was because for the first 25- 30 miles on the car on my way home I left the parking break on, but when the black marks on the rotors went away from that, the sound is still there.

It's not too noticeable, only when the radio is off and the revs are low with window cracked or t top off at low speeds, so I'ld like to get this fixed before it's a big problem. I was just thinking the rotors might just need to be resurfaced.....good thing i came across this post.

Anyway what do you guys know or think?

any additional help will be greatly appreciated
Dan

 

[Dan Ciezniewzki]

i've been having the same problem with my 01 nsx that i bought in sept with 6500 miles on it and noticed it around 7000 to the present 9400. I got it from an acura dealer with the warenty, do you guys think the warenty would cover this?

At first I thought it was because for the first 25- 30 miles on the car on my way home I left the parking break on, but when the black marks on the rotors went away from that, the sound is still there.

It's not too noticeable, only when the radio is off and the revs are low with window cracked or t top off at low speeds, so I'ld like to get this fixed before it's a big problem. I was just thinking the rotors might just need to be resurfaced.....good thing i came across this post.

Anyway what do you guys know or think?

any additional help will be greatly appreciated
Dan

 

[NSXT]

After leaving the parking brake on for a while, I would expect the pads to be glazed or even breaking up and making your strange sound. Take off your pads and inspect them, or just plain replace them and have the rotors checked for trueness.

I left my parking brake on for an 85 second autocross once, and the pads were smoking significantly as I crossed the finish lights. The pads were disintegrating, and I had boiled the fluid as well.

If it winds up being a bad hub or wheel bearing, then yes, it will be covered under warranty.

 

[NSX-Racer]

If your dealer knows that you track the car you'll have to pay a bad wheel bearing yourself - look at the warranty rules from Acura/Honda (at least here in Germany).