Rotor doesn't turn smooth by hand - and squealing sound while driving

[Trevor K]

I'm trying to diagnose a squealing sound I have, that is rotational, that is coming from the front and is based off how fast I am going (higher pitched at higher speeds, lower at low speeds). When I am driving along the road, whether I am applying the brakes or not, I can hear a slight squealing (it is louder when I am next to something to echo it off of). I put in AC Delco pads/lines and flushed the fluid on all four corners about 20,000KM ago. When I did this, the mechanic (my neighbour) told me not to bother changing anything else since it all looked good when he looked it over, so I listened. I also had him show me how to repack the bearings, and he ended up doing both sides. Now, I don't know when the squealing sound started (As I drive 5000-7000KM on the Camaro every year), however this year I've decided to fix it. While I was swapping out my front tire, as I got a nail in it on my first day out for the summer, I spun the rotor by hand and you can hear it making contact with the brake pad when it rotates. Is this a sign that I need to change out the calipers? Or is it normal for there to be a little bit of contact/resistance? Other than this, the only parts I can think of, that haven't been replaced, are the rotors and bearings. I'm unsure what noise bad bearings make, I've always read it's a howl. And I definitely don't get a howl, it's a squeal. What are your thoughts?

[NINÅ]

Originally Posted by Trevor K

on my first day out for the summer, I spun the rotor by hand and you can hear it making contact with the brake pad when it rotates.

That’s normal. However you should clean and take a look at your bearings and spindles to make sure they’re OK. Then repack the bearings. Use new grease seals and new cotter pins.

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Originally Posted by Trevor K

I'm unsure what noise bad bearings make, I've always read it's a howl.

Bad bearings do make a howl/grinding noise, it’s ugly.

Maybe someone will chime in here about the brake squeal.

My priority is performance.

Performance pads squeal like a son-of-a-gun especially when coming from full speed to a stop, they’ll squeal during the last portion of the stop.



Happy Racing!

If People Drove Any Slower They’d Be Going Backwards

Fog lights are not driving lights. They look dorky. Turn em off slow pokes.

How bout those dorks too scared to drive without headlights on in the daytime!

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[campin1983]

Just a thought, but you mentioned things had been changed 20,000km ago, and you didn't mention rotors. How old are they?

I might suspect a warped rotor if its not pretty fresh, and especially if it wasn't serviced when you last changed the pads.


Another thing to check is if something is caught under the brake pad. It seems silly and obvious, but I've carried what appeared to be the remains of a screw around between the pad and rotor for months before.

[84 1LE]

Did the mechanic apply any anti-squeak lubricant to the back of the brake pads?If not then you will have metal to metal contact with the calipers & squeaking.Also built up brake dust will also cause squeaking sometimes.
If the rotors are warped the pedal would pulsate with the brakes appiled.Metal to metal contact squeaking changes a speed increases because the vibrations increase with speed.
Pads are suppose to contact the rotor or else you have a gap & the pedal will drop to the floor when you apply the brakes.A slight resistance is normal.

[Trevor K]

Originally Posted by campin1983

Just a thought, but you mentioned things had been changed 20,000km ago, and you didn't mention rotors. How old are they?

I might suspect a warped rotor if its not pretty fresh, and especially if it wasn't serviced when you last changed the pads.

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All I know is that the rotors haven't been changed in at least 100,000KM. Which means they might still be original to the car.

I'm guessing maybe I should go ahead and change them? The mechanic told me not to worry, since his visual inspection indicated they weren't warped. Although, short of them being blue I'm not sure how'd you see it being warped

Another thing to check is if something is caught under the brake pad. It seems silly and obvious, but I've carried what appeared to be the remains of a screw around between the pad and rotor for months before.

That's a good thought. Should I maybe rough them up with some sand paper in case they are glazed over, or does the friction between the pad/rotor remove any glaze?

[Trevor K]

Originally Posted by 84 1LE

Did the mechanic apply any anti-squeak lubricant to the back of the brake pads?If not then you will have metal to metal contact with the calipers & squeaking.Also built up brake dust will also cause squeaking sometimes.

No - there was no lubricant applied.

So I should take the pads out, clean the surfaces, then apply the anti-squeak lubricant? Where do I apply it to?

And I assume it's a common item at the auto store?

[Trevor K]

Originally Posted by NINÅ

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[color="RoyalBlue"]Bad bearings do make a howl/grinding noise, it’s ugly.

Well, it definitely doesn't sound like that then. So that's good to know, I was a bit worried it was something that was really serious.