Repairing a Wobbly Piano Bench

Place the bench on an even surface.

Open and lock its lid. Make sure it stays open during the whole procedure.

Unscrew the outer hex nut from one leg using the wrench and take the lock washer out.

Take the leg out and unscrew the inner hex nut.

Replace the washers with the new ones and re-screw the hex nut tightly.

Connect the leg to the bench again using the new lock washer.

Screw the hex nut a few rounds, but do not tighten it yet.

Repeat Steps 3 through 5 for all four legs.

Add a little weight to the chair or push it down with two hands.

Turn all four outer hex nuts one round.

Make sure the bench is balanced and repeat until all hex nuts are tight.

Close the lid seat on the chair.