Richard J Kinch wrote:
Jack writes:

My guess is that you should use Hydraulic Cement.

Wrong guess. So-called "hydraulic" cement is just (very) quick-setting
ordinary cement. Not appropriate for this type of repair.

Not so. Hydraulic cement expands as it sets, sets in the presence of
active water leaks, has about double the strength of ordinary cement
and is waterproof. It would work just fine in the OP's situation.
http://www.unitex-chemicals.com/cata...c_cement.shtml

Your suggestion of a two part epoxy repair would work, as would
polyurethane caulking. It all depends on the size of the crack and how
much he cares what it looks like.

R