To ensure adequate lubrication and to prevent a high operating temperature, the recommended amount of grease injected into a ball or roller bearing is approximately __________.

Correct Answer: Option B — 25-50% of the original void space in the bearing

Over-lubrication is a primary cause of bearing failure. Filling the housing to 25-50% capacity provides sufficient lubricant to maintain a hydrodynamic film while leaving adequate void space for thermal expansion and preventing the internal churning that leads to excessive heat generation and premature grease degradation.