REYCO T/A NUT

Its primary job is to secure the torque arm to the axle seat and the spring hanger, keeping your suspension linkage firmly attached under load. It's a 7/8-inch, Grade C steel nut with a flange that acts like a built-in washer to distribute clamp load and resist vibration loosening. You'd typically replace this nut whenever a torque arm is removed for bushing service or if the original nut shows signs of thread damage, corrosion, or loss of its locking ability.