Brain teaser time!

[Forty61]

Alright so here's something to ponder before I get in and look at it..

So the original noise I have been needing to address is that when I gently lay my foot on the brake I can hear a cyclic squeak from what sounds like the driver front corner. If I press a little harder the sound goes away. So I thought it would probably be a squeaky caliper from a lack of grease or a warped rotor.. I've been living with it because the brakes will need replacing soon so I've just been waiting to do everything at once.

Now the interesting part.. the other day driving home with the window down, while turning at speed on a ramp and not touching the brake I could hear the same or exceedingly similar noise. It stopped once the wheels were straightened out again.

What on earth could be squeaking under both of those conditions?

 

[MrBhp]

That's the indicator on the brake pad. When you turn the wheel under speed you are flexing the components just enough to make contact. Yep. Time for a BJ.

 

[Forty61]

That's the indicator on the brake pad. When you turn the wheel under speed you are flexing the components just enough to make contact. Yep. Time for a BJ.

The pads don't seem low enough to be hitting the indicator but I guess maybe they are.

Definitely time for a BJ, I should probably do the brakes too. Lol.

 

[GriffX]

and/or a seized caliper piston, the brake disc should push the piston back, but it doesn't do it enough.
I would measure and compare the L/R disc temperature after driving a few miles in the city

 

[JC SSP]

Could be as simple pad dust build up or the pad mounting clips making noise… or could be a hub bearing or even a dust shield rubbing on something.

A warped rotor usually vibrates when braking from higher speeds.

Sticking caliper could also cause a slight pull when braking. You can jack her up and spin the tire to confirm any resistance or as GriffX stated put your hand or temp gauge after driving around. The hot wheel one will be your sticking caliper.

 

[86GT351]

If the noise is rotational does it get louder as you accelerate?

 

[Kev555]

Ive experienced this if the brake disc has scoring on it where dirt etc gets trapped in the groves of the disc or pads develop ridges. Worn out pads cause this too as BHP mentioned. It could also be a wheel bearing on the way out, check it for play.

 

[Forty61]

If the noise is rotational does it get louder as you accelerate?

It is not present when accelerating, only under very light braking or turning at speed.

Ive experienced this if the brake disc has scoring on it where dirt etc gets trapped in the groves of the disc or pads develop ridges. Worn out pads cause this too as BHP mentioned. It could also be a wheel bearing on the way out, check it for play.

Hub bearings are a few months old, I changed those for the hell of it since they were so old anyway.

All good suggestions guys, I have some things to look at for sure..

 

[Kev555]

If bearings were replaced then as BHP said earlier possibly a dried up ball joint. I know the brakes on my pickup are currently behaving like your symptoms except for the cornering squeal. They were bloody awful squealing with a new set of good quality Ferodo pads so I changed them to cheaper pads and it no more squeal. About 3K later and they have started squealing a bit under light slow braking but not under heavier braking. I'm putting it down to scored discs as last owner must have run the pads to the metal. I plan to fit a new set of disc/rotors in January to hopefully cure it.

 

[WJBertrand]

I've had that squeak from brakes while turning on other cars, so far not on my Mustang though. I've always thought it was one of the pads leaning against the rotor due to cornering forces. Either the pad by itself or the whole caliper moving slightly as a result of centrifugal turning forces. Also check there's no play in the wheel bearings as that might let the rotor tilt over against the pads as well.

 

[stkjock]

brake shield dust cover? I had this issue on two different cars, somehow the light gauge metal bent and would hit the rotor under certain circumstances.