FL Vibration

[wylie]

I've got vibration that sounds like road noise as if you had a heavy treaded snow tire on.
It goes away when going into a right turn and then comes back when I straighten out.
Is this a bad wheel bearing ?
1999 GT 240,000 km

[BNaylor]

Hey Wylie you posted at the wrong forum at Tips & Maintenance so I had to move it to the regular part of the forum.

Sure sounds like a wheel bearing to me. I had one that was noisy when going to the left and it got quieter turning to the right. It was the right hub that was bad.

[wylie]

Thanx B
Any idea what parts I need?

[guitarfish]

The wheel bearing itself s/b the only part you need. Sometimes it can be an easy job, other times a PITA depending on how hard it is to remove.

[BNaylor]

Bearing & Hub Assembly w/ABS

[eippermx]

The way I determined I had a wheel bearing problem with my 99 GT:
1. Set your emergency brake, jack up the car and put it on a jack stand.
2. Grab the tire at 12 & 6 and see if you can feel movement. It won't be much. It'll feel sorta like the wheel moved a 1/32 -1/16 of inch or so in your hands.
3. Get a buddy to move the tire back and forth while you look up underneath and see if there is any movement in the steering components. If you don't see anything going on such as CV joint, steering knuckle movement etc. behind the tire then you've got a bad bearing.

That's mah story and ahm stick'n to it.

[guitarfish]

Yup, that's pretty much it. Do 6 & 12 o'clock, listen for a knock noise. It helps to compare to a car with a good bearing, if you don't know what a good bearing feels like. It will feel rock solid. However, I will say that as bearings age & wear, you will get some knocking noise doing this hand test, but still not hear or notice anything when driving. This just means it's still got life in it.

[richtazz]

The freeplay test is the best way to determine which bearing is bad. Noises can travel from side to side down the drivetrain. I've also seen bad bearings that get quieter when loaded or louder when loaded, depending on how bad they are, so that isn't always an accurate test either. Normally, they get louder when unloaded, as Bob described, so if it's louder turning to the right, it's usually a LF hub and vise-versa.

[BNaylor]

Tell me about Rich. Actually either test if not done properly can make a fool out of you. On the front bearings the rule of thumb is to replace both of course depending on mileage and some other factors. I've done the steering test and it turned out to be the opposite side hub or both. But in most cases it is fairly accurate. I've done the with the wheel pull test on lower mileage cars and it didn't reveal anything either but one of the bearings was definitely bad.

The best method to check wheel bearing wear is per the FSM or scientifically:

The proper way is to run a dial gauge fixture. Remove the wheel and put lug nuts back on to hold the disc rotor. Grab rotor with both hands pull in and out and then at the 9/3 and 12/6 o'clock positions watching the dial gauge. According to the GM service manual anything over .005" or .13mm means the bearings have wear and should be replaced.