drilling into welds????? and tapping them

[magimerlin]

OK long story short..
Water pump leak- no biggie right..

take pump off to find some idiot:smsoap::smsoap: has welded shut the lower water pump bolt hole(the one closest to the timing cover). So I guess I found the cause of the leak. They had a metal bar (held down by the timing cover bolt) holding pressure onto the water pump to try to get it to seal..

So question is what are my options? Can I drill into the weld and re tap it? What type of drill bit. My regular Dewalt bits barely even scratch it. Will a spot weld bit work in this situation? What about those double sided 1/8" bits to get a hole started? I have no idea how far in the weld goes either..

Thank you
Jay

 

[asp]

as a rule of thumb, the weld is harder and more brittle than the surrounding metal. it's no big deal to drill and tap weld, but make sure you use plenty of cutting fluid and go slow. having sharp bits will save you a lot of frustration too. HSS will work fine. if you're having a hard time with keeping the bit centered, grind the surface flat and hit it with a center punch where you want to drill.