My squealing brakes?

[Doozi]

Hey guys! I need your thoughts. When I bought my Runner, it had a pretty annoying brake squeal. I changed the pads last summer and things were perfect... improved brake feel and zero noise... until about two months or so ago. The squeal is back! It comes on with slightly more than light pedal pressure and I can get it to go away with slightly more pressure, but it seems to be squealing right at the everyday pedal pressure.

When I replaced my pads last summer, I skipped disc resurfacing because everything looked very good. I've done dozens of brake jobs and have never had this problem. I even, just recently, took the brakes all apart, cleaned everything, recoated everything with silicone (thinking that maybe my shims were loose), but the squeal is still there.

Any ideas?

 

[bergs]

If you can isolate which wheel, I'd be looking at an almost-frozen caliper. Could be the piston is not releasing correctly and causing the pads to glaze.

It's a bit far-fetched, IMO, but that's all I could think of based on the info you have provided.

 

[Doozi]

I don't think that I have frozen calipers... I've been paranoid about that after reading all of the posts I've come across so I checked everything out and found no evidence of any of the pistons sticking.

I'm just wondering if I should bother resurfacing the discs or just replace them. Logistically, it would be easier to just replace them, but definitely more expensive. If I did replace them (or resurface them), there would be no issues using the current pads, right? Just "bed them in" as normal?

 

[bergs]

Deglaze the pads if you're going to do anything with the rotors, be it replace or resurface. All pads glaze to some extent and you might as well start fresh. You can scrub your used rotors as well. Just be sure to try and get some semblance of a crosshatch pattern on both sides of the rotor.

I got to thinking a little more about this today and was wondering, since the squeal has come back twice, do you have some kind of specialty pads (racing, severe duty, etc) or perhaps the other end of the spectrum, really cheap pads?

 

[Doozi]

The first episode of squeal was with the stock pads which I changed to Centric Posi-Quiet ceramics. After several months, these started squealing, too. I'm still trying to pin-point the source (it's been a little too cold to hang my head out the window these last few days!), but I'll find it this weekend for sure.

 

[Doozi]

So I ended up "deglazing" my front pads and rotors over the weekend and it stopped the squeal... for a few days! . I just heard it again tonight on the way home from work.

Here's a pic of pads before and after. I scrubbed the pads in a figure-8 pattern on 60-grit sandpaper.

Rotor before... lots of spotty friction material build-up.

Rotor after... hard to get a good picture of this, but I used one of those medium poly gator wheels on the end of a drill. The final result was much smoother looking than this and I only did the outside surface to see if it made a difference.

I also added a second set of anti-rattle springs to the top of the front pads.

Initial results were awesome! Great initial bite, very consistent feel, and ZERO noise! But after only about 80 miles the squeal seems to be coming back. I think it might be time for slotted rotors... I've read that they really help to keep the pads in great condition.

 

[KB084RUNNER]

Try a set of Toyota OEM pads.

 

[Doozi]

This all started with OEM pads. I'll try new rotors in a couple of months and that should take care of it... it's just a little annoying.

 

[kman55]

Good luck buddy, I know mine is usually due to pads or glazing.

 

[KB084RUNNER]

When you first install the pads how do you bed them in? Also did you replace all of the anti-squeal shims? I also use permatex synthetic brake lubricant to coat the back between the pad & shim. I also open the bleeder and retract the pistons fully then re-bleed.

My bed in procedure is 30 stops from 35-40mph gradually to 5 mph with about 1 mile of cool off driving in between.

I hope this helps. FWIW, I have done about 10 Toyota brake relines and no squeal with OEM pads and the above procedures.

 

[Doozi]

My bed-in procedure is about the same as yours, but I probably do closer to 20 repetitions. When I do a pad replacement, everything gets cleaned, re-lubed, new shims, etc. I didn't turn these rotors because they looked perfect and felt like new. They're the only parts I didn't touch so I'm guessing resurfaced or new rotors will solve this. I've done lots of brake jobs over the years and have never had to battle an annoying squeal like this. Aside from the squeal, everything is great... no vibration, no shimmy, no other problems and I'm paranoid about the "frozen caliper" issue so I pay specific attention to that.

Do slotted rotors present any new concerns off-road? Stuff building up in the slots or anything? Just curious.

Thanks again for all of the feedback, guys!

 

[bergs]

Well this is a bummer to come back to. Did you scuff both sides of the discs?


I would avoid slotted rotors personally. They're great up until the beveled edge of the slots are worn down a bit and at some point you get a horrible grinding type of noise every time you brake. You will wish you had the squealing issue again.

Haven't looked into cross-drilled rotors for these particular vehicles but IMO those are the way to go. I had them on two cars that were rather consistently subjected to abuse and had great results. Never tried them off road so no input there.