Help me identify this noise

[98EXPY 5-0]

My 98 Expy is making a ringing sound. It's sort of a squeal like a pulley, but it doesn't seem to change with RPM. I took about a 7 second video of it. It's hard to pick up though. As soon as the video starts, you hear the wind from driving, but also a higher pitched sound that stops before the video ends. That is the noise. In the video it sounds kind of like more wind noise, or a whistle but it's not.

http://www.youtube.com/watch?v=5ouajv531mI&feature=channel_video_title
* Sorry, I can't get it to embed*
There is sort of a sqeaking sound and a ringing sound. They can happen together or seperate and I don't know if they are related or not.

Neither one seems to happen when I am stopped. I have tried to let it run in the driveway, hoping it would do it. But it does not. I have also tried to slow down enough to cut out any wind noise and it stops then too. It happens at speed if my foot is on the gas or not, and if I am coasting and push the gas, it does not change.

I also noticed last night when I was backing into a parking space on a hill (so I was backing down the hill), I seem to have two different brake squeals, but that was the only time. It doesn't do it at stop signs or when I am driving, just when I was backing down hill and feathering the brakes. I don't know if that could be realted unless its the brake indicator vibrating while I am rolling.

 

[GAINMOB]

check your electrical system...may have some feed back coming through the speakers from something...

 

[98EXPY 5-0]

No, its not speakers. When I drive past something large with my windows down, I can hear the sound louder as it bounces off the object.

 

[panda24619]

wheel bearing? jack up the truck and shake the wheels. thermo will know how to do all 4. all i know is the front. they will shake really bad.

 

[tmajikman]

Could be your brake pad squeelers, pull your wheels and check the fronts and rears, Pad thickness, inside and outside pads, it sounds like a squeeler to me.

 

[mtondreo]

x2 on brakes. cheapest, easiest to check and fix

 

[98EXPY 5-0]

I took my Expedition on a fact finding mission trying to figure out the noises it makes. The ringing noise stops when I slow down to about 15mph or less. So to rule out a pulley, I was going about 30mph with no one around. I put the truck in neutral and shut it off. The sound remained.

To me, it almost has to be my brakes, or a wheel bearing. With the engine off, I can't think of anything else that could make noise while I am rolling. Especially because it won't make the noise when the engine is running but I am sitting still.

What do you all think? And how can my brake wear indicator be making noise when I don't have the brake pedal pushed?

 

[Thermo]

98Expy, right near the end of the video, did you get off the gas? The reason why I ask is I seem to hear a bad fan clutch. That would explain the "wind noise". But then, if it isn't making it while you are parked, that kinda rules out that idea.

As for the squealers making noise while driving down the road, unless you have cemented the pads to the caliper, the pads essentially float between the caliper and the rotor. So, as you hit little bumps or the wind passes through the caliper, the pads are able to bounce back and forth between the caliper and rotor. If you are down to the wear indicators, they could be touching and squealing.

 

[carlosshane1477]

That happened to me. something that is causing the relay to go wrong, and this is causing the car to not start. if you still don't know what's happening visit some of the Ford Expedition repair shops here.

 

[VTfireftr]

I also say brakes.

When was the last time you replaced the pads/turned the rotors?

Marc

 

[98EXPY 5-0]

I replaced the pads less than 2000 miles ago. Both front sides. Thats why I have a hard time believing its the brakes. I have been so busy the past week. I haven't had time to pull the wheels and look. I also haven't been driving it much, since it's a third vehicle that I just use for my part time side business.

 

[VTfireftr]

Did you do the rears? They also use discs.