Occasional brake noise??

[blupupher]

On my wife's 2012 Scion xB (43,xxx miles on original pads), over the past few weeks I have occasionally noticed an odd noise when braking.
It almost sounds like grinding, but not quite, maybe more of a grumble, but I don't feel anything.
It is not all the time, and I cannot replicate it regularly.
It is only when stopping and while at slow speed, seems to only happen when going straight.
As soon as I let off the brakes, it stops, and does not start when reapplied.

I have pulled all 4 tires, saw nothing abnormal, probably 1/2 pads still there. Fluid is about 2 years old (DOT 4) and is clear.
Today pulled all the pads. Again, nothing looked abnormal. Rotors look fine.
I did lightly scuff the pads with some 400 grit paper before putting them back on.

Any idea what else to look at?
Would bad CV joints do this? They seem fine, boots intact, no noise when turning.
All suspension seems fine.
I thought possibly the transmission is making some weird downshift, but don't think so (drain and fill @ 30,000 miles with Maxlife ATF, fluid still looks red).
If it was the transmission, it would not stop when I let off the brakes, right?


I have some new pads in my cart right now (Akebono ProACT front and rear) and debating just swapping pads and see what happens. Or is that just a waste of $100?

 

[Rolla07]

Noise is front or back? Take the calipers apart and re grease them. Make sure the pins move easily. Might be a sticking caliper. Also, put a little silglyde on the back of the pads and on the slide pins. Re-test after that.

 

[John_K]

Originally Posted By: Rolla07
Noise is front or back? Take the calipers apart and re grease them. Make sure the pins move easily. Might be a sticking caliper. Also, put a little silglyde on the back of the pads and on the slide pins. Re-test after that.


Had this issue with my Sonata and it was a sticking caliper.

 

[JC1]

Originally Posted By: Rolla07
Noise is front or back? Take the calipers apart and re grease them. Make sure the pins move easily. Might be a sticking caliper. Also, put a little silglyde on the back of the pads and on the slide pins. Re-test after that.


+1. Make sure there is no corrosion anywhere. Make sure the dust shields aren't rubbing agaisnst the rotor and make sure the mug nuts are properly torqued to spec.

 

[WyrTwister]

Were it me , I would follow the advice to inspect and lubricate the mentioned parts . But at almost 50,000 miles , I would not take it apart w/o putting new pads on it . I would not reinatall the old pads .

 

[The Critic]

If it was equipped with the Advics pads, they tend to be a bit noisy once the huge chamfer wears down. It is normal and I would not take any action.

 

[blupupher]

Originally Posted By: John_K
Originally Posted By: Rolla07
Noise is front or back? Take the calipers apart and re grease them. Make sure the pins move easily. Might be a sticking caliper. Also, put a little silglyde on the back of the pads and on the slide pins. Re-test after that.


Had this issue with my Sonata and it was a sticking caliper.

Hard to tell. I think it is the drivers side, but can't narrow it down to front or rear.

Pad wear appeared even, so don't think it is a sticking caliper.

Originally Posted By: JC1

+1. Make sure there is no corrosion anywhere. Make sure the dust shields aren't rubbing agaisnst the rotor and make sure the mug nuts are properly torqued to spec.

Everything is in place, no corrosion that I can see anywhere. I was hoping to find a stick or rock in the dust shield to explain the noise, but no such luck.
Lug nuts are torqued correctly. Cleaned off hubs and back of rims.

Originally Posted By: WyrTwister
Were it me , I would follow the advice to inspect and lubricate the mentioned parts . But at almost 50,000 miles , I would not take it apart w/o putting new pads on it . I would not reinatall the old pads .

I am leaning to that, I actually just bought some silicone brake grease to do several vehicles (Scion, my F150, mom's Saturn, brother in laws F150). It is actually quite easy to do the pads on this car, so does not bother me to remove them.

Originally Posted By: The Critic
If it was equipped with the Advics pads, they tend to be a bit noisy once the huge chamfer wears down. It is normal and I would not take any action.

Not sure what the stock pads are, but I see what you are saying. I think I will just lube the slides and such and leave the pads alone for now.

 

[blupupher]

So after I posted this 4 months ago, I had no more instances of this happening.

2 days ago the wife says it is making that noise again. I go for a drive, can't get it to make any noises.

I pulled all the pads off again, but since I had the silicone lube, cleaned everything up (pins, pads, backing plates) and put it all back together using the new lube.

Pads still look fine (they are still the original Advics pads), rotors have not abnormalities on them. One of the pad backing plates (drivers front, outer pad) had a little weird rub marks on it, so I scuffed it with some scotchbrite pads then steel wool to get it nice and smooth. The pins looked OK, slids in and out just fine, but one of the drivers rear lube pins was very dark and the lube seemed "stickier" than the rest.
Checked the wheel bearings as best I could, and they seem fine. CV joints look fine. All suspension components are fine.

All back together, and I have no abnormal noises.
Next day, wife and daughter say it is doing it again.

Only thing different this time is that I did not lightly sand the pads before reinstall.

I have read on several Toyota forums that this seems to be a common issue, some say it is a buildup of rust on the outer edge of the rotor (none on mine), cheap pads (again, mine are the original Advics), dry slide pins (mine were not dry, and have been re-lubed properly), or pad separation (no evidence of it).

So I am left with 2 options, just leave it alone as The Critic says, or spend $100 for new pads, and maybe another $100 or so for rotors.

And if I go new pads, do I go OEM Advics, Akebono ProACT (what I was planing on), Raybestos EHT (read a lot of good things about them here), or even something like the AAP Platinum pads (have read a lot of good about these also)?

 

[The Critic]

Install new rotors (Centric Premium) and new Toyota pads. Since you still have the factory shim kit, you can use part #04465-AZ114. They are about $45 shipped. The ones you have now are probably better, but they are 2x the price.

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