what's that screech?

I've got a screech coming from my front left side.

It occurs a few seconds after I push the brake pedal, but not right away.
It continues long after I release the brake pedal.
Sometimes it won't go away until I come to a complete stop.
It doesn't sound like the pads.

Again, engaging the brakes triggers it, but releasing them doesn't subdue it.

Any thoughts on what to check?

 

check pully bearings ac idler is bad to go out on 2.7 maybe others

 

hmmm....i just had the idler replaced a few weeks ago when the timing belt was done.

if it was bad, why would it only squeak when the brakes are applied?

also, mines a v6 3.4L.

 

I cant help ya there whats rotors n pads look like

 

Wheel bearing maybe.

 

well, it's getting worse and almost constant. i can make it happen by just tapping the brake pedal, but it also just starts on its own without need to touch the brakes. once it starts it will not stop until the truck is brought to a complete stop. then it begins again at around 20 mph or if i just as much as tap the brake pedal. it doesn't change frequency or seem to change relative to speed. it's hard to describe so i made 2 vids.

in the first one i am traveling at about 5 mph and using the brakes to trigger it.
in the second one, its just happening on its own.

http://www.youtube.com/watch?v=XfncDWw32R8&feature=youtu.be
http://www.youtube.com/watch?v=Eev8cc5qD7U&feature=youtu.be

 

also, i'm not 100% it's coming from the wheel assembly. just that it's coming from the left front.

 

Have you pulled the wheel off to take a look at it? Maybe something got caught in there? if not, can you see scoring on the rotor?

It could be a sticky caliper piston.

 

Sounds like a squeal tab on the brakes, i have had rocks get caught in the brakes to and do that till they grind away. It sounds like brakes to me.

 

check for rocks caught inbetween the rotor and the backing plate(rotor shield)

 

a stuck caliper was my thought. but it is now happening without even touching the brakes. it just starts up while cruising along. and i don't feel any pulling.

i've never had brake pad sensors that sound or act like this. it doesn't chirp. it doesn't even need the brakes applied to trigger it, although that does it for sure. and once it starts, it doesn't go away. it continues independent of all brake activity. meaning, if i take my foot off BOTH pedals and coast to a stop, it will continue up to the very end, then be gone, and start again at around 20 mph, without me even touching the brakes at all.

 

Have you taken the wheel off and looked for pebbles/gravel stuck behind the shield like Bmack suggested?

That has happened to me before when they gravel the roads for snow.

 

not yet, but i will today. i'm traveling, staying in a hotel, and my truck is packed up. so it will be a process to unload it, dig out the jack, and get the wheel off. all in 100 degree weather. that's why i wanted to get some opinions as to what to be checking for.

but yeah, wheel comes off next.

thanks all.

 

it was just the brake sensor. i wish i hadn't inquired about something so basic, but it threw me for a loop that it was going off even without engaging the brakes. i was told if the pads are almost gone, the sensor tab has the room to move around and hit the rotors just because of normal vibrations. fair enough.

thanks all for the help. next time my truck won't start, i'll come on here and ask: "why won't my truck start/" and you guys can answer: "put some gas in it"

 

Thats what i thought it was, glad you figured it out. Those damn things are annoying as hell, lol.

 

Glad you got it figured out, OP.