Grinding noise--CV axles or front bearings?

[TominMO]

On my stock blue 90 Festy, I'm noticing a grinding noise when driving. Can't really tell which side. It appears when coasting, whether in gear or in neutral. It goes away when I brake or apply power. Once I did hear a clunk. I'm hesitant to drive it until this is resolved.

The only CV boot that looks bad (i.e. boot is split and grease has definitely come out) is the outer drivers side. I'm guessing it's this. I don't really think it's bearing noise, because that would be constant, whether coasting or not, and increase with speed and decrease with slowing down. Also, I tried turning sharply left and right in a big parking lot while coasting, and it makes no difference whether the bearings are under load or not.

Your thoughts please.

[xlence]

Hmmm..I might have this exact same problem...ironically I didn't think it was a problem to be worried about because it started after I changed my front pads and rotors. I thought it might be the brake pad retaining spring/clip that is shaped like a V rubbing on the rotor since it sits over the rotor. I also assumed that the reason the sound goes away when I brake is because braking squeezes the pads closer to the rotor and this action pinches the retaining clip a bit lifting it off of the rotor... BUT now that you said what you said I think I was trying to find a simple answer and "rationalize" it in my head so as to not worry myself. Darn it

[doylerl]

The only grinding I have experienced was a bad wheel bearing race. I know you said it doesn't seem to matter whether under a load or not, but mine was the same way. I didn't notice it until I put new CV's in and then especially around corners it would grind, but would also do it just going down the road sometimes. Mine definately needed changed!

It would grind so loud, that it sounded like I was driving in the breakdown lane on the highway!

[batstiva]

Leaning towards bearings as well. My right side fronts were so bad when I changed them that one of them came out in pieces. Mine made varying amounts of noise, from a just barely audible grinding, to so freaking loud it was silly. When they decided to make noise, it pretty much didn't matter what I was doing, they were grinding. When they were quiet, same thing, they would stay quiet no matter what I was doing.

[Pu241]

Grinding noises generally bearings.
It's hard to pin down front or back, unless you have someone ride with you and have their head out the window.
From inside the sound resonates and is hard to localize.
No matter Tom, swap from parts car will get you up and running in short order.
Then we can do rear bearings at our leisure or find a competent shop to do the front bearings.
Can anyone in STL, or general area, recommend a shop to do the front bearings.

[Pu241]

Second thought Tom, we replaced a missing bolt in your driver-side caliper.
I wonder if the pad did not wear on that part of the pad, due to lack of compression force.
Resulting in a misshaped or uneven pad geometry.
Now that the bolt is in and the pad is now constrained it may be "dragging" causing a grinding sound.
Just a thought.

[TominMO]

Second thought Tom, we replaced a missing bolt in your driver-side caliper.
I wonder if the pad did not wear on that part of the pad, due to lack of compression force.
Resulting in a misshaped or uneven pad geometry.
Now that the bolt is in and the pad is now constrained it may be "dragging" causing a grinding sound.
Just a thought.

Yeah, that is interesting about the brake. Maybe now it's just getting the wear it didn't get before. In fact it started after we did the brake bleeding and added that bolt. I'll pull the LF wheel tmw and look at it. BTW it is definitely coming from the front; and I did the rear bearings and brakes when I got the car last year.

[Flyin4stroke]

when i was coming back from NC festiva madness i had what felt to be like the wheel locking up when i let off the gas.. I knew my axle boots were torn before i left but didn't have time to fix it took 1200 miles and a week later for them to start clunking when i turn.. But when i was driving home it felt like a wheel was coming loose for a 1/4 of a second and shook the wheel. I would say it is cv axles especially if you see the boot torn.. You can buy just the boot now too if you want a cheap way out i plan on just doing the axles and the bearings at the same time...

[TominMO]

when i was coming back from NC festiva madness i had what felt to be like the wheel locking up when i let off the gas.. I knew my axle boots were torn before i left but didn't have time to fix it took 1200 miles and a week later for them to start clunking when i turn.. But when i was driving home it felt like a wheel was coming loose for a 1/4 of a second and shook the wheel. I would say it is cv axles especially if you see the boot torn.. You can buy just the boot now too if you want a cheap way out i plan on just doing the axles and the bearings at the same time...

Thanks, but I really think it is a brakepad issue. Now that John mentioned it, it did sound like a brake pad. I'll check it out tmw. And I have two new reman axles ready to go on.

[FestYboy]

yes, typicaly a grinding noise will be brakes, whereas a growling/humming noise that changes pitch with speed will indicate a bearing.

[WmWatt]

To listen to the noise from a wheel drive the car along a wall. The sound is reflected back. Behind a shopping centre is one place to find a long wall. Drive in both directions to hear both wheels.

[TominMO]

To listen to the noise from a wheel drive the car along a wall. The sound is reflected back. Behind a shopping centre is one place to find a long wall. Drive in both directions to hear both wheels.

Right, good tip, I forgot about this. I'll go do it today.

[drddan]

To listen to the noise from a wheel drive the car along a wall. The sound is reflected back. Behind a shopping centre is one place to find a long wall. Drive in both directions to hear both wheels.

Beat me to it!

[TominMO]

OK, drove a long a wall both directions. Now I'm thinking RF wheel bearings. Also, when I turn right while coasting, taking the load off that wheel, the growling stops, which is further support for bearing wear.

[FestYboy]

i recomend you invest in a stethiscope... for future noise issues.