For decades, the lubricants industry has struggled to tame a critical but unruly test, ASTM D3527, designed to evaluate automotive greases. This high-temperature wheel-bearing grease test could be the poster child for bad behavior. Myriad attempts to better its precision and accuracy have had little success, and the method remains so stubbornly defective that in 2015 a proposal was floated in ASTM to abandon it altogether.
Instead, that motion was voted down and the test method renewed through 2020. Because flawed as it is, a lot is riding on D3527, explained David Turner of Citgo, who chairs ASTMs Subcommittee G on Greases. It is a core test for ASTM D4950, the 30-year-old standard and specification that defines automotive wheel-bearing grease performance. Passing the D3527 test is mandatory for service-fill greases seeking GC-LB certification from the National Lubricating Grease Institute. The test is cited by the U.S. military, auto companies and component manufacturers, plus its readily available. So the industry wants it to survive-if only it can bring it to heel.