Replace the belt dogs:
Turn the polygon shaft until the belt dog is easy accessable from side of the machine.
Loose the two screws on each belt dog.
Then replace the belt dogs, be careful that belt dog, is correctly placed in the timing belt, as shown in the picture.
Turn the polygon shaft until a belt dog is inline with reference 3.
Take off the bracket (see picture),in the back of the front plate.
Then mount the screw loosely to side plate of the synchrostar unit.
Slide the slot of the bracket around the crank handle and tighten the screw.
Now you have to release the tension of the synchrostar belt, by loosing the M12 screw.
Then release the tension of the body transport belts. The white arrow shows you where you can release the tension of the outside belt. The inner belt has the same feature.
Untighten the two set screws.
Loose sligthly the three M8 screws (1) first, then undo the M8 screw sligthly too (2). Now you can release the clamping force by turning the M8 nut (3) a little bit.
Now, you should be able to move shaft to the front of the machine and to replace both body transport belts.
Do not loose any other screws, as for example the red marked ones in the picture.