Cannot get my water pump to stop leaking at the bottom between the pump & front cover. Stock cover & edelbrock pump. Took the back off the pump, wire wheeled it put its pitted. Block sanded the pump housong clean. Silicone only on the back cover (did not have a gasket for it) & silicone & gasket pump to cover. Front cover to block appears to be OK. Leaks as soon as I start to fill it. Hsd the front cover off with the pump attached and it started leaking after re-assembly. i have done that befor & have been able to just redo the sealing between the front cover & block without touching the pump side many times. Pulled it apart after the leak cleaned & tried to seal as above, still leaks. car was not leaking before i pulled the cover off. Any ideas?