I have an '88 740 gl the brakes have started something interesting. They will push back on the brake pedal accompanied by a sound like grinding, but not like metal on metal at the rotor. it almost feels like the rotor has spots that are rough. The car also pulls to the right when it does this. Also it doesn't do this consistently and only at low speed with light braking, mostly like parking lot speed, but if I brake hard it goes away. It is inconsistent and hard to predict. I pulled the wheel and the rotor doesn't have any glaring issues. The brake pads need to be changed. but there is still pad left. When I turn the rotor by hand on the front left side it rubs ever so slightly stronger in one spot. So the rotor is a tiny bit warped, I can't see it when I turn the rotor, but can feel it. It is very subtle.

Any suggestions?

 

Make sure the slider pins are lubed, the caliper has to be able to slide back and forth, mine were dried out and binding.