Brake Squeal

So this has been going on forever now.

2006 4x4 V6 TRD Off Road.
Just the front brakes.
It sounds like a loud metallic screeching noise.
It does it only when it's cold. Once the brakes warm up it goes away.
Starts as soon as I start applying pressure to the brakes.
I've swapped out multiple pads/rotor combos by now (over the last 8 years or so). To include OEM, ceramic, EBC, Hawk. and for rotors, I've tried quite a few too.
When I install a new set of brakes the noise goes away for like the first 50 miles or so. Then it slowly comes back.
I've followed all bed in procedures (for the ones that have bed in procedures).
I've lubed the common contact points and installed the shims as required.

Help me

 

Do you sand the rotors clean with 180 grit sandpaper when installing new pads? There very well could be a micro layer of pad material built up on the rotors.

 

In my experience if brakes are squeaking its because of a "tight" caliper. Something is sticking and not releasing fully when you take your foot off the brakes. Could be a rusty retainer pin or a sticky piston. If your calipers are the original ones from 2006 it wouldn't be a dumb idea to replace them

The thinking is, when a caliper is not fully releasing the pads, at that wheel they get hotter than normal and the surface of the pad gets glazed over from heat. The glazed surface loses its friction characteristics and becomes micro-polished like a mirror. Then when that pad gets pushed against the rotor surface it vibrates and "sings" like a guitar string.

Squeaking is essentially a harmonic vibration.. thats why manufacturers use all types of springs and clips to try and hold the pad in place so it can move in and out, but not vibrate.. its a battle.. and sometimes brakes just do whatever the heck they want. They get used a lot, every time you drive the vehicle..

Take the wheels off and look at the pads through the back of the caliper. Look for uneven wear or slanted wear. That would indicate a sticky caliper. Look for changes in color side to side. Is one side red/orange and the other side normal? The red color can be a sign of overheating.

And if you replace the cals you may want to do the pads again. Once the friction material gets too hot its kinda been compromised and it'll never go back to being quiet

 

From the factory these truck come with 2 sets of shims.
One is a solid and the other is a slotted. You might try a set of OE pads with both shim sets.

Some vehicles are just prone to squeal.
Tacoma trucks aren't know for it. But you gat the occasional one that just "does".

 

Try using two spreader clips instead of one on each caliper.

Make sure the pad wear squealer tang isn't bent and touching the rotor.

Does your typical drive cycle include long waits at red lights? The heat soak can cause additional pad material transfer. If waiting for a long time, shift to Park and engage the parking brake.

 

Pad material transfer will usually cause a pulsation not a squeal

 

Definitely no pulsation. Only squeal. I thought it may be a sticking caliper or something but the squeal goes away as soon as pressure is let off. When pressure is applied, squeal starts, the more pressure there is, it gets louder till the truck stops. But once warm, no noise. That's what's wild.

I'll try everyone's recommendations and come back with a follow up.

 

post some pics of both your calipers

 

Did you use brake caliper slide grease on all pad to metal to metal end contact points?

 

Not trying to argue but I don't think grease is going to make pads quiet down. They don't use it at the factory and factory brakes last forever without making noise.

Unless the grease is under a protective boot of some sort (like a sliding caliper design) its just gonna get washed off anyway

The calipers are 20 years old, I'd start there along with a fresh set of pads

 

To perform a quality brake job its always a good practice to apply a film of brake grease where the metal frame of the bad rests on all the hardware...
Been a professional auto tech for 32 years...
Its all the small things that add up to a quality job....
If you do A & C, skip B, you have poor results...
My brake jobs dont come back squeaking......
Thats one of the first things you lean when doing brakes, what it takes to eliminate noise.....

Im not saying put grease on the pad material....
Even if it is the actual pad material contacting the rotor thats appears to be making the squeak, I would never skip that step...

 

I did apply grease to all metal contact points. I'll get pix of the calipers at the next opportunity...but thinking that's really the only thing I haven't replaced so far - so maybe that's the problem (process of elimination).

 

Thanks for the clarification, & knowledge...

 

Then why do literally no manufacturers do this when the car is assembled?

 

I thought you didnt want to argue...
Theres LOTS of things we do to make things better that the factory doesnt do during assembly.....
Its very common for a new vehicle to come in for brake squeak complaints.....
Been doing this for 32 years
Im not a new backyard shade tree weekend warrior guy....

https://www.youtube.com/watch?v=bLaQGWtd1O4

https://www.youtube.com/watch?v=qsozrTXfHoc
FF to 27 minutes...

 

How many time are you going to tell us you’ve been doing this 32 years?!

 

try not to, but when im questioned like my advice is "amateur hour".......
I dont pay attention who frequents the board, who doesnt know, or who knows....

Im not trying to be annoying, just giving you history of where my advice comes from.....
I dont think im special, but have a ton of knowledge to share, & im not even a gear / motor head...
I hate cars at this point, im only 52....

 

There’s quite a few members that have significant experience repairing automobiles. They just don’t advertise it. I even have a bit under my belt from many years ago.

Now back to the regularly scheduled program of fixing the squeal

 

Started when you were 20 huh?

Me too

 

Maybe you learned something, or not..........