Front door gate won't latch

Live in San Francisco where it is common to have these gates before reaching the front door. I am currently having issues getting the door to latch close shut without slamming it with the right amount of force. I took out the other end and saw that it works if I just don't together without the gates.

The gate and locks were installed in the 80s if that means anything. I spent an hour taking apart and cleaning the latch part (first pic) and cleaned around the area in pic 3. Tightened screws. All this helped a bit but not too much.