Inspecting and Greasing the Main Shaft

All Shindaiwa, Echo, and Stihl straight-shaft trimmers and brushcutters feature one-piece high-carbon steel mainshafts. Shafts are splined at both ends to minimize wear and vibration, and are usually supported by either four or five pre-lubricated bushings housed in an extruded aluminum outer tube. Shaft bushings are isolated from the outer tube by rubber anti-vibration (A-V) mounts. On most models, torsion control is pro- vided by either a hollowed or relieved mainshaft. Outer tube dimensions vary between models (refer to Specifications in the applicable Service Manual Appen- dix), but all tubes are manufactured from aircraft aluminum and are mandrel-drawn. This manufacturing process produces a seamless outer tube with consistent toler- ances, superior bend resistance, and a nearly flawless finish.