The primary purpose of seals is to

• A. Increase system pressure
• B. Seal the fluid of the system and to keep foreign matter out
• C. Color the fluid
• D. Reduce temperature

Answer: (B)

Seals are designed to keep the hydraulic fluid contained and to keep foreign matter out of the system. By preventing leaks, they maintain pressure and fluid level, which protects components from wear, corrosion, and contamination. This containment is essential for reliable operation of ALRE equipment, where clean, pressurized fluid is critical to performance.

The other options don’t reflect the main role of seals: they aren’t meant to color the fluid, and while proper sealing supports pressure, increasing pressure is not the primary function of a seal. Seals also don’t reduce temperature; cooling and heat management handle that.