Hello everyone,

I am about to do an almost complete overhaul of the power steering system in my e34: everything but the pump, box, and cooling pipe is getting replaced. This relatively drastic step is being taken as all of the lines are leaking. As I will be removing ALL of the old fluid, this raises the question of what fluid to use to refill.

Based on a couple of points I am considering using CHF 11S:
- CHF 7.1 was discontinued by Pentosin.
- Pentosin states that 11S may be substituted for 7.1 in a system as long as ALL of the old fluid is removed, as they are not miscible.
-- The source for that is this document from Pentosin: http://pentosin.net/pressreleases/PE...UIDE3_Rev1.pdf
- The new ZF reservoirs that are available from Pelican and BAV appear to be labelled for 11S.
- Pentosin states that the characteristics of 11S are better, being synthetic rather than mineral oil based.

The argument on the other hand is:
- There is the Febi/Bilstein M6162 fluid that is 7.1 equivalent. Some argue that it is the exact same stuff just with a different label, but I don't know that for a fact.
- I can probably just use the cap from the old reservoir that is marked for 7.1 on the new reservoir.

The question is, has anyone on the board encountered this same situation, and what did you do? The car does not have self-leveling suspension, so at least I don't have to worry about that.