Do i have a big problem???

IDo i have a big problem???I was changing the WATER PUMP with a litle help of a ''friend'',and he tight the bolt till BREAK the Aluminium part that hold the water pump.But the thing is that the bold i'm reffering to ,is the one that stay in the top of aluminium part(Don't know the name)and it seems that it only there to hold better the W.P.It's not leaking and doesn't seem to be getting bigger. and take it out its something i realy didn't wanted to do,so...
The engine its working fine till now ,but im afraid that this can be a problem someday.OR NOT????
I'll post some pictures soon. :angry4: