I have an commercial M98 action, with a side safety. Shown here:



The link goes through a small hole drilled through the action.

I was wondering if its a big deal to weld this up again?

Pic is too dark to see where you want to weld it, or why.

The link goes from the safety, up diagonaly through the action and locks the bolt.

Because its drilled a hole diagonaly through the action.

Thinking about moisture, rust..

If you are talking about welding up the hole that allows the safety to lock the bolt I would leave it alone. Many if not all of the MKX Daly etc actions have a hole (slot) to allow the safety to lock the bolt. The early ones forced you to take the gun off safety to open the bolt. Later ones the bar was altered so the safety no longer locked the bolt. Not sure if they ever stopped cutting the slot.

I lightened up your photo; there is no reason to weld up that slot. But no reason not to either if you really want to.

If you must block that slot just use some JB weld.

That is a modification the Swedes did to Mausers with military safeties. They left the military safety in place in most cases. I have sold hundreds of such guns, maybe even that one. The rod is very effective at locking the bolt down. Personally I would leave the safety there unless you're installing an M70 type.