HMSO Hydraulic Fluid

Probably the most unusual fluid we sell is Hydraulic System Mineral Oil.

This was first used in the Rolls Royce 1979 & up brake and suspension system, and later in various other vehicles that use a hydraulic system for power steering and/or power brakes, as well as some self-leveling systems.

The main applications of this are Jaguar XJ6 1988 & up in the power brakes, self-leveling suspensions, and starting in 1990, the power steering (the actual braking system is still DOT4); the Audi 5000 power steering 1985–90, and BMW Nivomat.

The best way to identify a system using this fluid is a reservoir lid that is green, or a sticker with a green drop. Audi and BMW may have a sticker that says CHF7.1, which is the German Pentosin equivalent. Later Audis use a synthetic version also made by Pentosin, CHF11s.

Mercedes-Benz uses a special fluid in their self-leveling systems, which we carry under the Mercedes part number. As far as we know, it is unique to Mercedes and not interchangeable with anything.

It is NOT SAFE to use anything else in a system that is designed for an HSMO fluid; we have seen expensive BMW Nivomat shocks and Audi power steering components damaged by incorrect fluids.

(There are also Hondas that use a special power steering fluid; we now have a source on that as well.)

We carry:

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Prices are subject to change without notice.