Cautions for Tightening Top Nut

The top nut, which holds the shock absorber's piston rod and upper mount in place (Photo 1), must be tightened at the prescribed torque with a torque wrench. A loose top nut will cause noise while driving, in the worst case damaging the shock absorber and/or the vehicle.

When tightening the top nut, prevent the piston rod from rotating along, by clamping the notch at its tip with a tool (Photo 2). In case of a damping force adjustable shock absorber: too much torque can cause distortion of the piston rod here, damaging the damping force adjusting mechanism inside it. As a precaution, please first tighten the shock absorber's top nut at the prescribed torque, before you install the shock absorber into the vehicle.

Please note that clamping the piston rod with a too big or small tool can lead to distorting it too. Also, be very careful not to slip off the piston rod's flat part, and damage its thread. If by any chance the piston rod ends up distorted, and the damping force adjusting mechanism fails, overhaul and piston rod replacement will be necessary.