Power door lock replacement

1999 k1500 4x4 Suburban. Both rear doors will not work on power locks. One was jammed so I disconnected linkage. My question is how do I replace actuator? After removing door panel it is hard to access them- but it appears that they are mounted on a metal plate with aluminum rivets which I could drill out to gain access. These plates are loose (actuators were repaired by dealer once under warranty). Can someone point me in the right approach and is there a good source for quality replacements? Thanks, Jim