Rack stuck or not, you should be able to push fuel through the fuel rack. It is essentially an open gallery surrounding the various pumping elements. Failure to move fluid through indicates a clog somewhere. Check your banjo bolts to make sure they are in the right spots and the correct type (IE: not a relief valve stuck where an open bolt should be)

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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]