точно незнаю но синяя(если не прозрачная)
то это скорее всего фиксатор резьбы крепления демпфера
в личку скину сайт где видел статью про ремонт демпфера(к сожалению поршневова)
может пригодится:)

Судя по приведенной информации рекомендую ничего не трогать и обратиться к специалисту.

Instructions for servicing the Stabilizer
Recommended oils: / Bel-Ray HVi light or 3w / Spectro Very light / PJ1 2.5wt

OIL CHANGE ONLY:
1) Remove all ten Allen or Torx head bolts holding the top cap on the body. (see diagram # 1). If they are corroded, a swift blow with a punch that matches the head diameter will normally loosen them up.
2) With the bolts out, twist the cap sideways to break it loose and lift cap off (oil will come out). (diagram # 2) 3) Empty the oil and clean thoroughly with solvent or contact cleaner. Clean all valving holes in cap and blow
out with pressurized air making sure to aim the forced air away from your face. 4) Clean the top seal thoroughly, re-grease and reinstall top & screws. (We recommend use of bullet tool). 5) Remove both bleed hole bolts (bottom of damper diagram # 3). Move the vane all the way to one hole, fill the
damper by injecting oil into the opposite hole forcing air out the other hole at the same time. (diagram # 4).
Scotts offers a tapered tip damper oil bottle for injecting oil, making this operation easier. 6) Reinstall both bleed screws. Manipulate the link arm side to side and feel for any air in the system. Remove
one bleed screw and hold upright so air will rise to the open bleed hole. Add oil as necessary. 7) Continue to switch bleed holes until the majority of air is gone. Optimum is to have only one small air bubble remaining when finished. IMPORTANT: If the unit is totally filled with oil (no expansion area) it can fade when it gets hot! You must allow a very small expansion area for the oil as it expands as the operating
temperatures rises.

В в свой роторник заливал вилочное 3W