This manual is for refilling OEM (original Brother) cartridges. For refilling BCH refillable cartridges, follow this link: Article 206736586
1. Identify the air intake, ink outlet, and refill spot. Air intake has a white column in the middle. When you push down the column, it will release air pressure inside cartridge. Ink outlet is a white opening on the bottom. If you draw a parallel line from ink outlet, refill spot is at the back of ink outlet.
2. This is what a Brother cartridge looks like when we take the outer shell off.
3. Use a knife to pry open the outer shell and then use a plier to remove some plastics and expose the refill spot.
4. Drill a small hole through refill spot. Do not drill too deep. You may rupture the ink bag.
5. Fill up syringe and insert into the drill hole. While injecting the ink, use a pen to press down the white column in the middle of air intake, otherwise the pressure will stop the ink flow.
6. Use hot glue gun to seal the refill hole.