I have a 2004 F150 screw 4x4 lariet, very low miles. When the vehicle is put into reverse and starts to move the rear brakes makes a grinding sound as if the emergency brake is on or lilke the sound it makes when the brakes are wet. Once foot is off brake sound is gone. I have had the roters replaced, also had the brake pulsating taken care of. Now a new loud noise only in reverse. Any help out there.

 

New pads and rotors need to be broken in. Plus, reverse is working the pads against the "grain". Kinda reaching here, try and back up a ways and ease onto the pedal for a few yards, see if it clears up.

 

No this didn't work anyone out there with any thoughts would be great.

 

Does this happen all the time or only after sitting overnight? Overnight, or if sitting for a day or 2 when damp outside can do this. After a few brake apps. it goes away. Surface rust on the rotor face. I have also had rocks and mud become imbedded inside the rear disc parking brake drum wedging between the drum and parking brake shoes after offroading. This caused a sound similar to yours. Hope this helps .

 

My brakes do the same thing and I have 12k on my truck now. No idea whats up.

 

Had you try engaging the parking brake while in motion to see if it does change pitch noise?

You may have rust inside the parking brake shoes...

https://www.f150online.com/galleries....cfm?gnum=7516

 

Mine is definitley not the e-brakes. I started getting a groove on the disc right in the center. I have my inspection in June and still under warranty so I hope they swap out the rotor so I can put on new pads but if not I will just swap out brakes and rotors.