my brake sensor light came on, pulled pads and the rotors replaced with new OEM parts (NOT from eBay)..no issues...went together fine except the retention springs kept coming off, after several attempts I got them to stay on...drove a few miles hit the brakes firmly,no pull, but bad pulsing in brake petal and a very bad grinding noise...sounded like the inner dust cover Might be hitting back of one rotors? ....

I pulled the wheels....no issues...turned rotors by hand..normal tension against pad..could find nothing that seemed to have been grinding...but it grinds bad....rotors have no grooves (again new) and look to be breaking in smoothly...for the few miles on them.

on the the drivers side, the retaining spring is gone...came off some how the passenger side is fine...
would this missing retention spring cause the pad to “shift”making the grinding and the pulsating in the petal? I can not find anything wrong by visual inspection, Any ideas?