If the original alum threads are damaged, rethreading them will not let them hold the same amount of torque as if in original condition.
Therefore, you may have to install a thread coil, ie, Helicoil, or a threaded insert.
When drilling/tapping alum, there is an alum tapping oil one can use to prevent binding and breaking the tap. Makes working with alum like a hot knife in butter.
The Helicoil set includes the drill bit of the correct size, the Helicoil tap, the installing tool, and a set of thread coils. You supply, and must, a small punch and hammer to knock off the installing tab. By not doing so will damaged the bolt being used and the thread coil.