... basically you have to lay down and look up under where the rear brake pedal mounts to the rail/bar and you will see a threaded rod attached to the end of the rear brake lever shaft, it takes a 10mm on the one end and a 12 mm on the other ( if memory is correct). I adjusted it there making sure to not run the threaded rod out of the nut in the metal bracket that holds it and keeps it from turning, I made sure the threaded rod still is completely in the nut just flush to the end so the retaining nut has full holding strength. With mine there was only approximately 3/8 inch adjustment (without running the threaded rod further down into that retaining nut) but it was enough for my needs. I 'think' the rear brake lever shaft is splined and sets on a short splined shaft arm but have not taken the things off to get to it to find out, if it is splined then it might be possible to rotate the shaft to raise it up or down?