Considering that T-800s are made of some sort of future titanium-alloy the weapons of the Sisters would bounce off in the best case.

Composite T-800s can lift cars and similar things, so injuring them shouldn't be a problem.

Especially since most zombies have shown to be able to be penetrated by conventional bullets and since those sisters have no special durability feats, he could most likely just pin them to a wall with his pipe and kill them with their own chainsaws