Abstract : A literature survey was made on the lubricity of low-viscosity fluids and pump wear. Viscosity, volatility and purity data were obtained on commercial fuels and pure hydrocarbons. Four-ball tests showed the effect of load and speed on initial, steady-rate, and equilibrium wear regimes. Ball-and-cylinder tests uncovered advantages for certain commercial antiwear additives; in four-ball tests additives gave some improvement in wear at lower loads, but no improvement in scuff load. Two nitrogen compounds showed some antiwear effect but no anti-scuff activity. On the other hand, some of the sulfur compounds reduced scuffing in the four-ball test. Ryder gear tests confirmed the good performance of the antiwear additives in reducing gear-tooth scuffing. In the Vickers vane pump test, a commercial JP-5 fuel was clearly better than the reference Bayol 35 in spite of a lower viscosity. The addition of 1% bright stock to Bayol 35 gave somewhat better performance. Lubricity additives at 0.1% were considerably more effective.