The new bulkheads fit perfectly in already drilled holes so below is "my" sequence in replumbing.
I had to first cut out the old bulkheads, because no amount of yanking would allow them to be unthreaded.


Above left, bulkheads in the drilled holesholes, and 1" males to glue the PVC to, and right shot, elbows glued into males, with the upper half of the unions unions glued in.
Below bottom half of unions glued in, and unions threaded together.

I had to first cut out the old bulkheads, because no amount of yanking would allow them to be unthreaded.


Above left, bulkheads in the drilled holesholes, and 1" males to glue the PVC to, and right shot, elbows glued into males, with the upper half of the unions unions glued in.
Below bottom half of unions glued in, and unions threaded together.


