Adjusting Pneumatic door closers sounds like a difficult task, but really it is simple. You will need a screwdriver and follow along with the steps below to guide you through the process.
Step 1 - Adjust the Bracket
Begin by trying to adjust the bracket. Make sure that you open the door completely. Use the stopper to keep it open or have someone hold it for you as you work. Use a screwdriver to loosen up the screws that are holding the bracket and move it back and forth to the desired position. If it is held in by a pin, you can just slide the pin out and move it back and forth and secure it when you find the desired spot.
Step 2 - Adjust the Cylinder
If you want to slow it down, you can use a screw driver to turn the cylinder screw clockwise. Although if you need to speed it up, then you can work it counter clockwise, until it tightens.
Once you are finished you will want to test out the door. Open and close and adjust until you find the desired speed.