Q: SUV has new brake pads and rotors. Making a grinding noise when I brake but, not everytime

This circumstance is not unusual and I suspect is often related to the use of non-OEM rotors and non-OEM brake pad material and also the failure to re-apply factory specified shims and/or appropriate anti-squeal compounds and lubricants. Unfortunately, once non-OEM parts and materials are used, and thus in essence an "experiment" is set up, brake noise can be a result. If there is a warranty, of course your first recourse is to simply return to the vendor and have them resolve this problem. Missing shims should be considered and the possibility of a lubricant solution should be considered. If the pads are non-OEM and are of low quality materials, for instance if they have lots of metallic chunks, such low quality pads will be inherently noisy. If the noise arises from the brake pad material, really the only solution is to remove the pads and install the more appropriate OEM friction material (rotors should be re-surfaced and/or de-glazed if any pad substitution is attempted). If you would like a professional opinion regarding this issue, please simply request a brake noise diagnostic and a certified mechanic will be dispatched by YourMechanic to evaluate your brakes and pinpoint the cause of the noise.