I don't have a full A7,C. Just to be clear, the BCV was established to a Raid 5 volume that needed to be replaced. The 1 track on the M4 BCV position never went to 0. I don't have access to the machine. The best I can show for the A7,C command is:
You can run, can we safely replace drive script to check if there is any risk in replacing the drive.
Considering all the other raid member are fine, the drive can be replaced. Once it replaced, you can do a full establish to the BCV.
Do you have Hotspare invoked for this drive and fully synced?
Still you need more clarity, please engage PSE lab for further assistance.