Chirping rear brakes HELP!!!

[rvaedge]

Alright, I just put new cross drilled rotors and ceramic brake pads on my 1997 XLT. Everything works great, it eliminated the squeel my brakes had before, less stopping distance, more responsive, BUT there is an incredibly annoying chirping noise coming from the rear brakes. It ONLY occurs (atleast at an audible tone) when I apply the brakes. It sounds like a crickett leaves in each of my rear wheels. The faster I am going the faster the chirping is when I apply the brakes, and as the car slows so does the chirping. It is really annoying. Any ideas of what it could be. I thought maybe the e-brake, but why would it do it only when i apply the brakes and not all the time, I went back and checked the assembly and everything was put on correctly, the calipers are in good condition. Its been 2 weeks so I doubt its the pads and rotors meshing or anything (especially since the front doesnt do it). I'm stumped. Give me some HELP!!!

 

[Slybarger]

It sounds to me like what your hearing is, the hot gases escapeing through the holes in the rotors. I haven't ever run cross drilled, or slotted rotors. But, you said the speed of chirping, is realative to the speed of the truck. It is my first guess.

 

[rvaedge]

I doubt it is that because I only hear it coming from the back and if the heat coming through the holes made noise, I would definitely hear it in the front as the front does more of the braking anyways

 

[Slybarger]

As I said I don't know for sure, I don't run them, but it's not just heat coming out of the holes. Brake dust and gases blast through there, at what I would think is a pretty good speed. Is it possible that, because it's the rear with less brakeing pressure applied, somehow causeing the sound? With cross-drilled rotors front and rear, got a proportioning valve? Dial a bit more to the rear and see what happens. I could very well be totally off here, but I keep remembering writeing on a chalk board, and that damn screech, if you didn't press hard on the chalk.

 

[BuffaloXplorer]

Are you POSITIVE it is the brakes making the noise? A bad u-joint will cause the same chirping and slow-down/speed-up while you do the same. Also, you may not notice it when you accellerate, as there is more noise to contend with (i.e. exhause/engine/etc)

 

[rvaedge]

I am not positive, but it started right after I put the new brakes on and it sounds like its coming from the area around the rear brakes. As for the proportioning valve, I dont know what that is. Where is the U joint located?

 

[BuffaloXplorer]

If your 97 is the same as my 96, you have 5 u-joints alltoghether - 2 on the front driveshaft, and 3 in the rear split-driveshaft. If you follow the driveshaft from the tranny back, you'll see " + " shaped joints - these are your u-joints.

You don't have a proportioning valve inless you installed it yourself, and if you did you'd obviously know it. It allows you to balance the braking system by moving pressure from front to back and vice-versa - ever played Gran Tourismo? You can buy & install a brake balancer on any car there

 

[Heavymentill]

You could possibly need new shoes for your E-brakes. The e-brakes are on the inside of the rear rotors.

 

[rvaedge]

Thats what I was thinking, but would the noise only happen when I apply the brakes. Wouldnt it happen all the time. Also would it slow down and the car slowed down.