Re: 1930 7-45 suspension dampers

Posted by Owen_Dyneto On 2011/4/12 11:02:07

kts68, note my correction to my post above, the higher viscosity Mobil hydraulic oil is SAE 20, not 30.

Chemistry of lubricating oils and hyraulic oils not an area I'm particularly familiar with, but we have a couple of other chemists who visit here, so perhaps they have more info.

There are many varieties of hydraulic oils for all manner of specific applications. They vary from simple vegetable oils like Canola up to pure synethetics mostly for aerospace and aircraft use. But the general run-of-the-mill hydraulic oils are based on mineral oil with additives to enhance various properties. Most important properties are low compressibility, ease of de-aeration, low foaming, etc. so additives are added to enhance these properties, plus for compatibility with materials of construction, etc.

Motor oils (non-synthetic) are based on particular cuts from crude oil, again with all manner of additives to control foaming, reduce friction and corrosion, and control viscosity range as a function of temperature.

Personally, I'd never even consider substituting a motor oil in an application that calls for a hydraulic oil.