JJ3

Good day to all. I'm a new member to this forum. I have a 2008 LS460 with 140,000 miles on it. I have recently experienced a grinding/humming sound coming from the front left drivers side. The sound gets louder as speed increases. It picks up at about 40 mph. I tested the car around curves to see if the weight distribution would change the sound and it stayed the same mostly. my first thought was it could be the wheel bearing going out so I had my mechanic take a look at it and it indeed was going out. He also discovered my upper and lower control arm bushings were shot. I had him replace the wheel bearing first to see if that would make the noise go away and it didn't. The very next week I had the upper and lower control arms replaced(4 total) including the ball joint that is pressed in the steering knuckle since I needed them anyway and hope it would make it go away but it didn't either. I got an alignment, tires balanced and put a new set of michelins on the front. I'm lost at the point to figuring out what it could be because it's incedibly annoying to drive it. If anybody has had a similar or the same problem or has something to say please feel free to comment. I would very much so appreciate it.

comotiger

Have you checked the brakes?

roadfrog

That pretty much leaves brakes as the culprit. If your car was AWD, then that would be another issue to consider.

JJ3

Thanks guys for the responses! I actually had a pair of ceramic pads put on there as well recently. I haven't put new rotors on there yet though. So the only parts I haven't replaced yet are rotors, caliper and the outer tie rod end and the sway bar bushing and link since that is really all is left that I haven't replaced yet. Can rotors make noise even when you don't apply the brakes? In other words it can cause vibration even while coasting?

Doublebase

Sure. A rotor will make noise if they are coming in contact with the pads die to a stuck caliper or pad that is hanging up a little bit. Does it feel like the brakes are slightly engaged when you're driving? Does the car not coast as easily?

Amd sometimes the the rotors can contact the backing plates and make a scraping noise. Where you just had your brakes done I think I'd certainly consider giving them a good look over, some times aftermarket pads don't fit right and can cause a lot of noise problems.

JJ3

Thanks a bunch Doublebase. The car does brake on its own at lower speeds between 20-45 mph mostly. I'm assuming that has been the brake assist feature. I'm not entirely sure. The rotor itself looks really rusty and seems like it's been on the car for a long time but I usually change pads and rotors at the same time. I definitely will look over the car and see what's going on when I get the rotors replaced. I told my buddy about it and he gave me a new pair of Raybesto rotors to help me out. I will post the results after I get the rotors installed.

Gillz460L

Have the wheel bearing checked as well. If your bearing is shot there is good chance of noise and vibration.

JJ3

Preciate it Grillz. I'm hoping it's not that since I just replaced it but it's worth double checking.

JJ3

I had the rotors installed and it seems to have gotten rid of some of the noise but the noise is still there. My mechanic concluded that the wheel bearing is defective and the culprit. It sounds very disappointing considering I just installed a new one almost a month ago but I will have to replace it.

sktn77a

iTrader: (2)

I doubt it. Brake assist only works when you push on the brakes (hard).

Doublebase

I had a similar situation occur when using an aftermarket wheel bearing...the thing only lasted 7,000 miles before it became loose. I ended up getting my money back and bought a Koyo, which supposedly is an OE bearing. I paid $225 for the wheel bearing, which is 1/3 of what I'd pay for a Lexus wheel bearing....25k miles later and it's doing great.

JJ3

Yeah I do have a similar situation. I bought a Timken wheel bearing and it went bad the same day I had it installed. I'm hoping this one works. Ive never heard of Koyo but if it aint broke dont fix it! Its lasting a lot longer than my Timken. I should be getting my new bearing today.