Riding Lawn Mowers

YTH20B42. What is the part number for the Arm Break part for my mower deck? I can not even find a manaul on this tractor. It is not a YTH20B42T. Mine does not have the "T" at the end. The "T" model manual does not show this part. My blades continue to rotate because the pads are so worn. Anyone know where i can find these two breaks? They are similar to PART NUMBER: 532197261, except mine does not have a round hole for the bolt. it is a elongated hole to allow for adjustment. Thanks guys.