I've always heard that brake fluid goes bad real fast (IIRC, it absorbs the moisture in the air).

What about power steering fluid?

Can you buy a large container and use it over the years? Or, like brake fluid, should you only buy what you need for one use?

  • How large is large @RockPaperLizard? Power steering systems don't need much.
    – GdD
    Commented Sep 19, 2018 at 7:23
  • @GdD I'm thinking either a gallon or a quart. Commented Sep 19, 2018 at 15:05
  • A quart is a sensible amount for a car owner to keep on hand, a gallon not so much @RockPaperLizard. Unless you have a leak or flush the system it will take years to use a quart.
    – GdD
    Commented Sep 19, 2018 at 15:09

2 Answers 2


Power steering fluid can be stored for several years in a sealed container. However the standards for power steering fluid vary by manufacturer and model year. The vehicle you are driving 5 years from now may not use the same fluid.


No, it is not as hygroscopic as brake fluid.

However, it can degrade over time - especially if the level is low and it gets overheated, It tends to go brown.

Normally the fluid will only need topping up if there is a leak - I still have a small (1 litre) container I carry in my car due to a previous leak which has been fixed.

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