unlikely to have shagged the m/c simply because its been pulled all the way in.
Either use a speed-bleeder (one-way valve) you can get these from Supercheap or ebay for less than $30. These are good.
Better still - soak about 1/2 the brake fluid out of the m/c. Then take off 1 caliper at a time, take the pads out and use a small g-clamp to squeeze the pistons all the way back in. Watch the fluid level in the m/c - it will rise as the pistons get pushed back into the calipers. Do the same thing to the other caliper.
This will push out every single bit of air trapped behind the pistons. Re-fit the pads, fit up the calipers and then top up the m/c. A few easy squeezes of the lever will force the pistons back out and after maybe 1/2 dozen squeezes - the brakes should feel rock-solid. Keep an eye on the fluid level in the m/c as you do this - may need topping up a bit.