Water Pump Won't Take Grease

[Pilotdave]

I just installed a new leakless water pump on the Tudor. It came with instructions for greasing the rear bushing.

The instructions are to loosen the packing nut and pump grease into the brass fitting until it comes out around the shaft. One is supposed to do this every 500 miles.

I can't get the fitting to accept any grease - what little goes in dribbles back out through the nipple on the fitting. I removed the fitting and see that there's grease in the cavity behind the fitting.

Does this sound like a defect in the pump? How might I repair it?

Thanks much.
Dave