Customer house was built in the 50's. Old sub-panel has a feeder cable that doesn't have a neutral. Just 2 hots and a bare ground wire. All the neutrals and EGC's land on the same bar. I want to separate the EGC's from the neutrals. So I was going to pull a EGC from the main panel to the sub-panel. Add a ground bar to the enclosure, land the EGC from the main I pulled in. Then land all the EGC's in the sub-panel to it. And use the bare feeder cable ground as a neutral. Is this OK? Thank you for your help.