To be safe I'd just go to the dealer and get a bottle. The P/S reservoir only holds 1/4 quart or less, so cost isn't really a big part of it.

Have you flushed out the steering or replaced the filter lately? Always good to do that.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
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'13 ML350 Bluetec - 95k - dad's (OC-98k)
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