Can you see fluid movement in the reservoir when the engine is running? If so, the pump is moving fluid and your problem is likely in the steering box. It's highly unlikely to be the pump or lines - you already changed the pump and the hydraulic pressure is sufficient to blow through any "blockage" that may be in the lines.

If you changed the pump and had an air pocket in there, it's possible you're airbound. Try running the engine and turning the steering wheel lock to lock several times to "burp" the system.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]