Ludwig timpani I assume? This is a balanced-action pedal, which means the pressure from the head should be balanced against a spring in the pedal itself. If it is not staying in tune, a very likely problem is that the head itself is not tuned to the right range. Check that first. The ranges of the drums are
[ 32: D-A. 29: F-C. 26: Bb-F. 23: D-A ]
Some other brands may give you a range of a 6th rather than a 5th, but the range is very similar.
If the drum is actually in the correct range then the spring tension is off (somebody decided to turn the acorn without knowing what it did). Find someone who knows what they are doing to walk you through it. You shouldn't need to use the screw with the 'break pads' if everything else is working.