99 E300 Turbo Diesel, 152000

Hello diesel friends!

I don't have any fuel coming out of the delivery valve closest to the bumper. Odd thing is when I loosen the valve, I get plenty of fuel squirting out. Whenever I tighten the valve back down (35nm) nothing. I tried this several times - same result.

This comes after I had the delivery valves apart to replace the O-rings & crush washers. The pressure valve carrier & the piston came out when I pulled out the pressure valve holder - but I'm pretty sure I put everything back in correctly. I checked it against another valve. I checked all other valves- they are working correctly. I get plenty of fuel out of every line except the 1st one. Any help appreciated!! Thanks - Tim