they can leak from the pump, the steering box and the lines. Be careful of the steering box, a leak there often actually comes from the high pressure line. This is the most common leak easy fix and about $50 for a new line, replace the low pressure line while your at it. The hi pressure line usually leaks from the end that attaches to the steering box, if it is leaking it will be fairly wet and dirty.
m

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Martin Ingram
Colorado Springs
2005 320 CDI
2006.5 VW Jetta TDI
1991 560SEL (179000 Sold)
1972 280SEL 4.5 ('The Lead Sled' 320000 miles when sold.)
1972 220D (225000 when sold)