I replaced the motion drive belt on a 99 model Murray 42" lawn mower. The mower moves as it should now, but when I push the clutch/brake it doesn't help stop the mower. The mower moves forward in any forward gear and moves in reverse, and stays put in neutral. Somehow, I have removed the functioning of the brake/clutch. I can shift it from neutral to be in gear, and back to neutral, without the clutch/brake pedal. How do I add back the functioning of the clutch? Thanks.