Unscrew the stopper .
Unscrew the first bolts you see .
Slide the carriage .
Screw the bolts .
Put back the stoppers .
And , yes , I fear I have no track left !
Am I right ?
I have a few photos for you, then I will write something that should help.
Photo 1 is me pointing the screw in the center of the brake.
Photo 2 is two marks on the ski showing the position of the heel before I release the heel. That position is for the SX 91s. By making those marks you have a starting point.
Photo 3 is the base plate that the heel slides on. My finger is on the side towards the tip.
Photo 4 is the heel off of the base plate.
After you put the two marks on the ski of the starting point like in photo 2 take a screwdriver and turn the center screw counter clock wise a quarter turn. This will let the brake lift up enough to disengage the teeth from the base plate now you can slide the heel back a fraction. Before you try to turn the center screw back you will have to make the teeth on the brake line up with the teeth on the base plate. If you can not get them to line up you may have not enough track left. Good luck and you can always ask more questions.