Adjust swinging door. Thanks again for posting this! I used the same mounting holes as the previous owner, because the door material is a hard steel that i don’t have any tools capable of drilling into. The cover may be held on by the paint. Remove the retaining screws from the plates with a phillip screwdriver. If its a concealed in top jamb closer (such a jackson 20-330) you will need to order another closer as they are fixed spring size. Manufacturers make door closers with closing and latching speeds that are infinitely adjustable within a certain range as determined by the strength of the spring that actually does the closing. Twist the adjustment screw in a counterclockwise direction one full turn to lessen the spring tension on the door.
How door closers work
But if the door is only partially opened and released, the sweep + latch are both too fast and the door just slams shut. All the best to you, and again, thank you for commenting.