Rear wheel squealing - 986 Forum - The Community for Porsche Boxster & Cayman Owners

wrs986 · 06-01-2019, 01:06 PM

When I did the test drive on my 1999 boxster base there was a very annoying squeal coming from the drivers side rear tire. It was independent of applying the brakes and cornering. The seller said he had his Porsche mechanics look at it and couldn’t find any problem. When I picked it up a week later no squeal at all and nothing since I got it home. I had new tires put on. Nothing on the drive home from the tire shop. Then last week I picked my daughter up from school and it started faintly as I was leaving the school and by time I got home from a 15 minute drive it was incredibly loud. Metal on metal squeal. Again nothing to do with the brakes or cornering. I took it out this morning for a quick drive around the block and no squeal.
When it got loud the last time I drove it, it wasn’t a consistent squeal it had a bit of a in and out wobble squeal as the tire rotated. I haven’t tried to pull up on the emergency brake yet. The only consistent element to this was the outside temperature. Both times it was squealing it was high 70’s. When I drove the car with no squealing it was high 60’s low 70’s.

piper6909 · 06-01-2019, 01:11 PM

Quote:

Originally Posted by wrs986

When I did the test drive on my 1999 boxster base there was a very annoying squeal coming from the drivers side rear tire. It was independent of applying the brakes and cornering. The seller said he had his Porsche mechanics look at it and couldn’t find any problem. When I picked it up a week later no squeal at all and nothing since I got it home. I had new tires put on. Nothing on the drive home from the tire shop. Then last week I picked my daughter up from school and it started faintly as I was leaving the school and by time I got home from a 15 minute drive it was incredibly loud. Metal on metal squeal. Again nothing to do with the brakes or cornering. I took it out this morning for a quick drive around the block and no squeal.
When it got loud the last time I drove it, it wasn’t a consistent squeal it had a bit of a in and out wobble squeal as the tire rotated. I haven’t tried to pull up on the emergency brake yet. The only consistent element to this was the outside temperature. Both times it was squealing it was high 70’s. When I drove the car with no squealing it was high 60’s low 70’s.

I once had a pebble caught between the dust shield and the rotor. Your symptoms sound very similar.

SC-986 · 06-01-2019, 05:51 PM

I had a similar high pitch squeal coming from the right rear several years ago. Couldn’t get a firm diagnosis on source of noise. Ended up replacing the wheel bearing and that took care of the problem.

tonythetiger · 06-01-2019, 06:01 PM

Brakes or bearing. The come and go makes me think bearing. Easy fix if you stop driving it

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piper6909 · 06-01-2019, 06:25 PM

Could also be the bearing. If it is, you'd most likely have play in the wheel.

wrs986 · 06-02-2019, 04:28 AM

Thanks for all your suggestions, it makes me wonder if it is something in the dust shield or the bearing needs to be replaced why the former owners mechanics couldn’t find the problem. Would a wheel bearing be intermittent like this? Both suggestions make sense to me.

Starter986 · 06-02-2019, 05:12 AM

Quote:

Originally Posted by piper6909

Could also be the bearing. If it is, you'd most likely have play in the wheel.

Play? You mean rocking it side to side... back and forth. Wobbly? Thanks!

piper6909 · 06-02-2019, 05:38 AM

Quote:

Originally Posted by Starter986

Play? You mean rocking it side to side... back and forth. Wobbly? Thanks!

There are a couple symptoms of a bad wheel bearing. The most common is a moaning sound related to speed. The other is play in the wheel, but you'd have to jack it up to check for it. Sometime the play isn't there, but usually the noise is.

Most recently I had a wheel bearing go bad in my Subaru with no symptoms at all, except it failed PA annual inspection. The mechanic pointed out to me that the wheel is wobbly. I had to see it for myself. It had play up and down as well as left-right. It wasn't the ball joint, nor the tie rod. He was actually surprised that when he test-drove it he didn't hear anything.

piper6909 · 06-02-2019, 05:45 AM

Quote:

Originally Posted by wrs986

Thanks for all your suggestions, it makes me wonder if it is something in the dust shield or the bearing needs to be replaced why the former owners mechanics couldn’t find the problem. Would a wheel bearing be intermittent like this? Both suggestions make sense to me.

Yeah, my money is still on a pebble between the dust shield & the rotor. It could be the bearing, but you'd think the mechanic would have noticed it. It probably never occurred to him to look for a pebble.

One possible reason the noise is intermittent could be that when you go in reverse, it dislodges the pebble, and then over time it find its way back to that prefect place where the rotor rubs against it and causes the heat shield to basically harmonize and make the squealing sound.

wrs986 · 06-02-2019, 06:32 AM

The pebble theory makes the most sense to me I would think the mechanics would’ve spotted a bad wheel bearing when it was on the lift. I’ve had bad wheel bearings before on other cars and I’ve always noticed that they get louder when you corner. The sound didn’t change when I zig-zagged or cornered. Plus I would think a wheel bearing would be consistently noisy. This only has happened twice and I driven it about 10 times now around the neighborhood.

piper6909 · 06-02-2019, 06:50 AM

Quote:

Originally Posted by wrs986

The pebble theory makes the most sense to me I would think the mechanics would’ve spotted a bad wheel bearing when it was on the lift. I’ve had bad wheel bearings before on other cars and I’ve always noticed that they get louder when you corner. The sound didn’t change when I zig-zagged or cornered. Plus I would think a wheel bearing would be consistently noisy. This only has happened twice and I driven it about 10 times now around the neighborhood.

Yeah, and it doesn't cost you anything to look for a pebble. My wife's car had a pebble and I was amazed how polished the side against the rotor was! It looked like a tiny piece of a granite countertop.

Since you haven't heard it the last 10 times you drove it, maybe the stone ground itself down so small that it fell out. I wouldn't worry about it until it happens again. And if it does, drive in reverse for a while and see what happens. Then jack up the car and look for it. And while you're there you can check the wheel for any play.

wrs986 · 06-02-2019, 07:10 AM

Great suggestion. Thanks!

jmitro · 06-02-2019, 08:34 AM

if there is a pebble caught somewhere you should easily be able to see score marks on the rotating part. If you don't see anything on the outer or inner brake rotor surface, it may be all the way on the inside surface of the strut carrier adjacent to the outer CV joint

tonythetiger · 06-02-2019, 03:13 PM

and on the bearing, I have had two fail through the years, both times a rear. The first one was immediate, constant wailing noise, varied with speed. I knew what it was, waited three days to get the bearing and it was fixed in a day.
The next made the same noise...sometimes. it went away several times, then returned. I already had a spare bearing so we swapped it, sure 'nuff...bad bearing that you could feel in your hand, but no wobble and intermittent sound.
Go figure. varying noise with speed would be an indicator of either fault.
Point is, if you eliminate the pebble theory, that is your next likely spot, given the limited info we have here.

wrs986 · 06-02-2019, 05:33 PM

I agree, the previous owner thought it might be a bearing. Any idea what it would cost to fix at an independent shop?

tonythetiger · 06-02-2019, 06:47 PM

Quote:

Originally Posted by wrs986

I agree, the previous owner thought it might be a bearing. Any idea what it would cost to fix at an independent shop?

I think the bearing is about 50 bucks...you need a shop to remove knuckle and press it in, so a couple of hours and an alignment. I think everything was about 400 bucks, although another shop quoted me 700. That was the day they lost my business. If you don't supply the bearing, they will rape you on that...both shops let me bring my own, otherwise the bearing would have been 250 parts.

I'm talking S model, the bearings might be different for the 1999 base

wrs986 · 06-03-2019, 09:08 AM

I’ll get it upon a jack later this week and check the bearing. If it is the bearing I should have play in the wheel correct? Also when I spin the wheel by hand I should hear something? Maybe the previous owner knew about the wheel bearing and didn’t want to spend the $400+ on the repair since he was selling it.

blue62 · 06-03-2019, 03:03 PM

Quote:

Originally Posted by wrs986

I’ll get it upon a jack later this week and check the bearing. If it is the bearing I should have play in the wheel correct? Also when I spin the wheel by hand I should hear something? Maybe the previous owner knew about the wheel bearing and didn’t want to spend the $400+ on the repair since he was selling it.

First question: Not always.
Second question: Not always.

Gilles · 06-03-2019, 06:32 PM

to replace the rear bearings, if you remove first the half shaft you don't have to remove the hub carrier, this way you don't risk damaging the ball joint rubber booth and you will not require an alignment..

wrs986 · 06-03-2019, 07:18 PM

So when I get the car on a jack and check to see if there is any play in the wheel and/ or if there is any noise when spinning the wheel and I find I don’t have any play or noise I could still have a bad bearing? How do you know if you have a bad bearing if there are no signs?