indescribable brake squeal
 

first off i am not a noob of any sort. i have been a mechanic for a long time and i have dealt with brake noises of all sorts on many different cars. i started off a few years ago with all new brembo rotors and hawk hps pads. i didn't like them because they had a weak cold bite and they squeaked once in a while, it was bearable. i didn't have some of the calipers springs so i bought mazda oem pads with NEW hardware kit. the oem pads squeaked a little, nothing major but the cold bite improved so i dealt with the dust for over a year. i was about to go to a bigger brake set up when i thought i should give the turbo brakes one last try with different pads. mind you i don't drive the car often so each set of pads has only a few hundred miles on them.
i recently got EBC red's front and back and put them in, they were great. for the first 2 minutes then i heard the loudest screeching coming from the front brakes. it sounds like dragging a 500lb metal desk across the floor! so i put the mazda pads back in because of an auto x day i was going to. noise went back to normal levels. then i figured i should have the rotors cut. cut them yesterday and reassembled everything. went for a road test today and it started out good. i went real easy on them, with light pedal pressure. most of the time brake noise would go away if you stepped on the brakes harder. when i stepped on them it got louder until i lessened the pressure. so i have newish rotors that have very little miles on them which don't have corrosion or rust because the car is garaged. i have new hardware with shims and springs. brand new pads front and back, which aren't cheap junk pads.
what is confusing me is only the front right is making the most noise. the rears have the same pads and they are quiet. i never cut the rear rotors. after i cut the front rotors i did have the sides mixed up so it can't be a side specific rotor causing the noise. i broke them in for about 40 miles today, so i will drive on them more tomorrow but everybody is giving me the " what the fuck" face when i pass by. i even made a pedestrian grab their ears when i drove by, and this was at 5 mph in a parking lot. i went on the highway and under light pressure i don't get any noise at first, then i hear a soft screeching. i would settle for that, but when i need more braking force it gets absurdly loud.
ANY other possibilities? i am about to junk the stock brakes, they work fine just noisy as shit.

yeah man im having the same problem. my right front 4 piston brake is UNGODLY loud. it almost sounds like a whistle or whine but a lot louder and metallic. its a odd noise i can hardly explain my self. it started happening when i swaped out my front rotors. the rotors came from my parts car, so i dont know the brand. they seemed to have been almost brand new(pads looked new too) aside from the rust from sitting out side. i can also apply light pressure and it gives the little squeak squeak noise, but as soon as i put even moderate pressure it starts to get LOUD.

I have tried pretty much every method possible and i'm getting frustrated. Today i'm going to use a lot of the brake quiet goop and see what that does. I even lubed the edges of the pads thinkin that would reduce friction between the caliper and pads.

Some pads are just noisy, especially some performance pads. Not even the best brake job (hardware, syl-glide, grease, brake quiet, etc.) can cure that. I take it your bearings aren't loose (would cause brakes to vibrate) and sliders/bolts are fine?

Just fyi, any professional automotive technician would lambast you for calling yourself a mechanic when referring to yourself as knowledgeable.

Just sayin', not trying to be an asshole. :)

I am fully aware that some pads are inherently noisy, the front right side is ungodly noisy. I have searched through posts for two days before i posted. I would be ok with normal levels of brake noise. If any of you heard this you would think a train was pulling in.

I am aware that the correct terminology is "technician". I was using a more commonly used word associated with mechanics

And no the bearings were recently repacked and torqued to spec with no play. There are no sliders since i have turbo calipers and the "pins" are fine. Bolts are clean and tightened properly.

Are you sure your calipers are operating fine? No suck piston? Why not jack up the car, and spin the tire to see if you can see any contact points where the noise is being made.

thats a good idea^ but anyway i found these videos i made on my phone a couple weeks back. its got some of the sound on them, although it sounds louder in person.

http://i561.photobucket.com/albums/s...0602091946.jpg

http://i561.photobucket.com/albums/s...0602091944.jpg

i have spun the wheels in the air and the pistons aren't stuck contacting the rotor, but today i will see if there are any pistons not moving outward. they are original calipers and when i put in new pads a few years ago i was able to compress them but never checked to see if they were hanging up and causing uneven pressure across the pad area.

hey unren not to put your car noise down but mine has got you beat. i know that in person it's louder but if i made a video it would probably sound all distorted from being so loud.
on a good not i did have a small breakthrough. yesterday i decided to check the calipers to see if all the pistons are moving freely. upon doing so i managed to get the right caliper piston almost fully extended because i was paying attention to the left one and had the pads out. yea i know stupid me, but i didn't think they were moving that much because i did look at both sides after i pumped the pedal a few times and the right side barely moved. all except one bastard piston. it came out and touched the rotor, so i attempted to push it back in. it said i don't feel like going back in. So it seems that the pistons didn't move freely and only moved enough to push a new pad to the rotor. i also think that maybe the pistons unequal travel was causing uneven pressure across the pad, which is why the brakes were extremely loud on just that side.
Luckily for me i had an extra set of used calipers at my garage. so i put that right side caliper on and checked it. i reassembled everything with disc brake quiet, sanded the pads to it had a fresh surface and brake cleaned the rotors. i was tired after so i finally road tested it today.
i took it easy as i always do, then picked up a little speed and applied medium pressure from about 30 mph. the noise moved? it moved to the left caliper. The noise level also dropped significantly from before. which to me is a good improvement. so i drove for about 20 miles and it didn't go away, except on the turn before my street i gave it medium to heavy pressure and there was no noise! i'm sure the noise is still there but at least it went away when i got on the brakes. whereas before the harder i stepped on it, the louder it got until i released the pedal.
so my conclusion is the pistons in the caliper not exerting equal pressure across the pad, causing a resonance. i will either rebuild the calipers or just get remans and see what happens.

awesome, im gonna deff have to pull those off and check the movement on the pistons again. they seemed fine when i checked em before, but ill be more thorough this time. thanks to everyone in this thread.

Make sure u dont make the same mistake as me and take all the pads out. Use a small piece of wood or something. Or a worn out brake pad. U will probably need someone to pump the pedal while u watch the pistons.
Hey Unren, my brake noise level has gone down to about the same as in your video. It used to be so much louder. I still think that all the noise can be reduced even more

ok thanks for the advice man