This because of a rubber bung that is inside the brake pedal. I've just taken my pedal set apart to remove it. It took about 20mins to do but I'm still finding the pedal requires some considerable amount of pressure to use (nowhere near as before I removed the bung).
You need to remove the 24 screws on the bottom, all of which are phillips heads and you you'll also need an adjustable spanner and a 6mm allen key to take appart the pedal once inside, you'll also need to take the brake peadal plate off as well and I think you need a 2mm allen key for this.
Be careful when putting it all back together, the wires inside have routing channels and they need to be seated in these otherwise when putting base back on you can cut through these.
Also, as a disclaimer, this voids the warranty with Logitech. It is worth it as the pedals a vastly improved.
