I have a 1998 mercedes SL500 theres a grinding noise coming from the front passanger side wheel but the rotor and pads seem fine and can't find where its coming from

These cars a rear wheel drive. A grinding in the front could be the wheel bearings. Inexpensive to do yourself ($35 for Beck Arnley from Rockauto) but does require skills to remove bearing races without damaging the hub and properly packing the new bearings with grease. Please also check your lower control arm and ball joint. The older Mercedes have an issue with the control arms breaking near the ball joint mount. This is due to plugged drain holes and rust from water. While