uttadms31

I had a question about a sound coming out of my rear wheels (see video link below). This is noticeable at low speeds and when I spin the tire by hand as in the video. Note that both sides make the same exact sound and volume. I thought it was the backplate rubbing against the rotor so I hit a screwdriver hard all the way around and the sound didn't decrease at all...maybe it's touching more towards the middle of the wheel which can't be accessed around the periphery of the backplate like what I did. I know my rotors are rusted bad, but I have at least 4mm left on the pad. It doesn't squeak or make this sound when I brake while driving. So if I go into changing the rotors (and I may as well do pads) is there anything else I should look into? Braking performance is excellent at the moment, and I don't think it's the wheel bearings since both sides are making identical sounds and there's no play at all when I wiggle the wheel around. This sound has been going on for 1-2 years I think. Thanks.

Slamrod

iTrader: (11)

Sounds like brakes if you ask me. Most of the braking power comes from the front so loss of stopping effectiveness in the back wouldnt really be noticable especially considering it occurs over a long time span.

If the brakes are indeed worn down then go ahead and replace the pads and rotors and be done with it. Be sure to rent a caliper compressing tool from autozone (free), some will argue that you dont need it and that you can use needle nose pliers. Ive done both methods and let me tell you - if you live where corrosion occurs, youll 100% want to have the tool. The needlenose method probably took me longer than it would have taken to drive to autozone and back twice.

maximaham

iTrader: (1)

brake drag, possible warped rotors or brakes

uttadms31

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I don't think it's brake drag since I haven't changed rear brakes in over 100k miles (mostly highway miles) and I still have 4mm pad left. I also get decent fuel economy...27 mpg. I think with all the rust on the rotor it may be hitting the backplate near the center which I can't get too.
So hopefully a pad/rotor swap fixes this and I don't have to deal with calipers, wheel bearings, etc.

LWilspeed

I'm pretty sure that is your backing plate (unless your inner pad is worn down more than you can see). I had a very similar noise on my 4th gen and it was the backing plates. I gently pushed them with my hands to bend them back a little. If you push one side too far the reaction is that somewhere else on your backing plates it will be pushed in - so do it all the way around the rotor, forcefully but evenly. The screwdriver with hammer may not have really moved the backing plate enough to stop the contact.
On a side note - i had one backing plate so rusted (around the axle tube) that it had no structural strength. I could push it back away but it would "fall" back and contact the rotor after going over a speed bump or pothole. I ended up having to remove it to keep the noise from happening. It isn't ideal to not have the backing plates so i would try to salvage yours if possible, but it isn't the end of the world if it is rusted out.

uttadms31

Ok thanks I'll try to bend it by hand after taking the wheel off. There was a ridiculous amount of rust that was falling down when I banged the backplate with the screwdriver.

asand1

iTrader: (1)

Disc brakes shouldn't spin that freely. I think your brakes are hosed.

uttadms31

Brakes or bearings are hosed? There's no roaring noise while driving nor play in the wheel when I wiggle it but I saw your rear brake video where you said if the hub itself using the studs spins around more than a couple times the hub/bearing are bad (though I have only spun the wheel not the hub itself at this point). If the brakes are indeed hosed how does that make the discs spin more freely.

DennisMik

iTrader: (2)

I'll join the group that says you have bad brakes. The scraping noise is not constant as the wheel rotates, the noise starts and stops during the wheel rotation. This is common with brakes. If the backing plate were making the noise, it would be constant. That goes for the wheel bearing too.

You said you looked at the brake pad and it had 4 mm of material left. Was that on BOTH pads or did you only check the one that is easy to see? At 4 mm of material, you are getting real close to having to replace the pad.

I'm thinking that the free wheeling rotation is because the caliper guide pins are corroded and preventing the caliper from sliding and re-centering on the rotor. Corroded guide pins are also the reason that one brake pad wears out faster than the other.

Daniel VQ30life

iTrader: (2)

if I'm reading this correctly, my guess is warped rotors

uttadms31

UPDATE:
I replaced my rear brake pads, rotors, and slide pins/boots last night. I'm thinking the rusted/warped rotors were to blame. I actually measured 6 mm on both pads on both sides even though it's been over 100k miles since I replaced them (mostly highway miles)!
The right side had one slide pin that was rusted/corroded. That piston pushed in fine afterwards. The slide pins on the left side looked in good shape, but I was unable to press the piston in even though I took the cap off the brake fluid reservoir and used the proper caliper tool. I ended up using the old pads along with the new rotor (that 6mm will probably last me a very long time). Looks good to go back there now.
I'm assuming my brake pads are indeed working back there even though one piston couldn't be pressed in, correct? When I brake the car doesn't drift at all to one side and it's smooth/no squealing. My front pads have never wore down fast in the past. Thanks.

Slamrod

iTrader: (11)

If one of the pistons couldnt be moved, then that pretty much means its seized. A seized piston will either allow no braking, or the brake will be clamped all the time and wear your rotor to nothing. Id look into rebuilding that caliper if i were you.

uttadms31

I forgot to mention, it was odd that the piston spun fine with the tool, It just wasn't pushing in enough to the point where it could fit with the new pads on