Radiator drain tap stuck - am I being stupid?

[Ruairidh Dunford]

It is important to support the starting handle when you knock the cotter pin. Do not rely on the aluminium housing which can break very easily if the handle is unsupported. A bit of tube around the back of the pin held on a block or resting on a jack at the right height gives the support needed. I learned the hard way a long tome ago!

I second this advice, I have seen so many nose cones destroyed, because of the cotter being hit with a hammer.

Much better to use a cotter pin removal tool.