Water pump 86 300E Anything special?

[ChinaClipper]

Folks, the fun just keeps increasing....I noticed a pool of coolant under my car after doing an oil change. I suspected the water pump and found about 3/8ths of an inch of free play on the pully and evidence of coolant being spun off.. I have not changed one like this before, anything special about it? Seals O rings etc? Also, is there anything that normally has to come off to replace the pump or gain access, that could be replaced/ upgraded? Thanks Scott