The pedal is mounted to a shaft. The shaft is held on each end by clamps that are mounted to the base. Those clamps have a screw running through them just under the shaft. By tightening those screws you cause more friction to the pedal. Also, there should be a spring on the expression mechanism that helps oppose gravity. (varies depending on model)
George
Organs
Hammond B-3/145
Hammond Super B (MIDI Controller)
Yamaha FX-1 - TM-1 x 2
Synths
Korg Triton Pro
Yamaha P-80
Native Instruments Soft Synths;
Akoustik Piano, Electrik Piano, B4II,
FM-8, Pro-53, Massive, Absynth,
OPXpro, Mtron