Brugger test criticised for hydraulics

Lubrizol and ExxonMobil scientists have criticised the Brugger test for hydraulics.

The oil and additive majors used a recent Tribology conference in Germany to question the validity of the performance test for hydraulic fluids, according to Lube Report's Richard Beercheck.

The test is used to establish anti-wear efficiency but, according to Lube Report, ExxonMobil and Lubrizol claimed the test does not bear much reality to real-world conditions for hydraulics.

In particular, it is largely based on putting fluids under extreme pressure, a condition not considered (or apparently required) in the blending of most hydraulic products.

Lube Report stated Alan Barber of Lubrizol was particularly critical of the test after presenting research which showed none of the commonly used hydraulic pumps come close to the conditions set by the Brugger test.

He also pointed out that in order to pass the test, fluid manufacturers were required to add sulphur-based additives to cope with the extreme pressure conditions. This introduces corrosive and de-stabilising elements to the fluids which would not, normally, be required - facts also supported by an ExxonMobil expert who presented at the conference.

According to Lube Report the comments themselves were criticised by Brugger test supporters. However, the experts remained adamant that Brugger was unrealistic as a general hydraulic screening test and, while the test is currently specified by only a limited number of OEMs, an issue was raised with the intention of preventing wider specification of the test by OEMs.