Tapping a new thread

[andy-xr]

The part of the inlet where the ISCV bolts to has stty threads and I cant get a good seal. The threads were for fine M4 bolts.

I fancy redrilling and tapping to M5 as I have a load of course bolts that'd fit fine. But I've never done it before. Is it just a question of redrilling out the holes and keeping it straight then using a tap set to set the pitch, or should I cover and redrill the ISCV and manifold it bolts to?

[andy-xr]

Its a bit loose and the bolt isn't really gripping after a medium tap so that's why I was thinking of going up to m5 really

[andy-xr]

Goodo, thanks v much