Clean the area around the mechanism and the mechanism itself.
After removing the circlip, remove the kickdown switch.
Using tools, loosen the lock nut.
Tighten with a torque wrench (1) adjusting bolt with a torque of 10 Nm, while holding the piston from turning. Then loosen two turns and re-tighten the adjusting bolt to 5 Nm.
Loosen the bolt 2.5 turns.