Lubrication fundamentals

A: A: Alkaline cleaners strip or neutralize EP additives, and that shows up first as surface fatigue. B: Hydrogen embrittlement doesn’t fit the steel grade or environment. C: There’s no electrolyte path or dissimilar couple doing the damage. D: Residues can be ugly, but they don’t explain micropitting this early.

A: A: Oscillation kills hydrodynamic wedges, so you lean on boundary protection. B: Circulating oil looks good on paper, but there’s no speed to build a film. C: Dry films wear off fast at these contact pressures. D: Oil mist won’t stay put once the load comes on.

A: A: Mixing thickeners is where field failures start, not at the bench. B: NLGI grade is consistency, not load rating. C: Polyurea works fine in many bearings when specified correctly. D: That temperature limit is a myth.

A: A: Pressure can look fine while one branch is starved. That’s the blind spot. B: Low pressure catches dry running quickly. C: Over‑pressure protection is inherent once the pump stops. D: An empty tank shows up as pressure loss.

A: A: Dents equal stress raisers. Life drops fast once you pass the threshold. B: Corrosion is secondary in a lubricated rolling contact. C: Seals care, but bearings pay the price. D: Size and count matter far more than chemistry here.

A: A: Water plus ester equals acid over time. Yellow metals suffer first. B: Shear stability is generally good for esters. C: Polarity is why esters lubricate well. D: Temperatures aren’t high enough for cracking.

A: A: Different bearing executions, different rules. That’s the disconnect. B: Blindly trusting the datasheet is how seals get destroyed. C: Placeholders exist, but you can’t assume that here. D: Forcing grease past seals creates more failures than it fixes.

A: A: Speed builds the wedge. Load is low. Film wins. B: Boundary shows up when speed drops or load spikes. C: There’s always some lubricant influence here. D: EHL depends on contact and pressure, not grease versus oil.

A: A: Thin film equals contact, contact equals excitation. That’s your 3%. B: Aeration adds noise, but not in this signature. C: Viscosity shifts are minor compared to contact effects. D: Churning changes losses, not the measured NVH spike.