A number of years ago I had an 89 260E with the same engine as you. Here is the thread where I posted my PS pump replacement notes and photos. Post #9 reports the actual results,

Checklist: PS Pump Re-Seal
http://www.peachparts.com/shopforum/tech-help/63549-checklist-ps-pump-re-seal.html

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2008 E350 4matic / Black/Anthracite

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Gone but not Forgotten:
2001 E430 4matic, 206,xxx miles, Black/Charcoal
1995 E320, 252,xxx miles, Black/Grey
1989 260E, 223,00 miles, Black/Black