Grease Fittings

[dlfrisch]

I poked a needle into my stock Ford grease fittings ( to make sure they weren’t plugged), but when greasing, I don’t know if grease is entering, it just squirts out around the fitting.
I would like to change the stock grease fittings and install Zerk type. How do you remove the factory fittings an install the new Zerk type ? It seems as though they are just pressed in. Can anyone help?
Dave