The top nut holding the piston rod and the upper mount on top of the shock absorber plays a very important role. If this nut becomes loose, there is a possibility you may hear unusual noises, or the shock absorber may failure to perform or in extreme cases cause damage to the vehicle.

For this reason, please tighten the top nut with a torque wrench at the appropriate torque. Please periodically check and tighten the nut. Recently a few customers have started to worry about their top nut becoming loose, and some trouble have started to appear because of a ‘double nut’ situation.

(Photo 1) demonstrates what a ‘double nut’ situation is. After tightening the lower nut, another nut is screwed on top to lock the lower nut in place. Trouble has started to appear when screwing on this top ‘locking’ nut.

When tightening the top ‘locking’ nut, (Photo 2), the lower nut is often held by a spanner. Doing so at the incorrect torque may twist the piston rod or even pull it. This has been quite common among damping force adjustable shock absorbers.

Compared to a fixed damping force system, the damping force adjustable mechanism is thinner because it is found on the inside of the piston rod tip. Because of this, if excess torque is applied there is a possibility of the piston rod from becoming deformed and/ or the damping force adjustable mechanism becoming damaged.

In extreme cases, the piston rod top will also become damaged and the piston rod will need to be replaced and overhauled. Even if this happens in during the shock absorbers warranty period, it will not be covered and the cost will be covered by the owner.

To avoid this kind of problem, you should use only the top nut included in the product, and tighten it at the appropriate torque. Please periodically check and tighten the nut. Do not use an extra nut, as in the ‘double nut’ situation.