This setup is one of the worst designs for a drive and braking system repertoire put out. Weedeater, to my knowledge has no service info out, which makes a service tech rely on his knowledge on how systems should work to solve customers problems. It has been at least 3 years since I have seen one of these, so my memory may be a little off. The brake cable should activate the brake arm to stop the forward movement. Sorry, but I can’t remember if the cable is hooked directly to the arm, or through another component. You will have to trace the cable from the front to the back of the mower, and then if it is not hooked to the brake arm, figure out what connects the cable to the arm. When the brake pedal is pushed, it should activate the arm, which will push the dowel pins, which will tighten the brake pucks against the rotor. On a side note, if my memory is any good, not one of the units that I worked on, was worth repairing if it was brought in as a nonengine problem. Sorry for the bad review and my poor memory, but in my opinion this is the worst designed mower ever to be put on the market. Good luck and post back if you have any other questions, I will try to help you out.