Copper or aluminum washers both should be fine. Is the valve on the left with the exposed ball the new one? I'm curious how that can work w/o fuel leaking out of there.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked