R107 280SL 1981 cleaning fuel system

[Roger Camilleri]

I am cleaning the fuel system including refurbishing the pump/accumulator unit, i removed the pipes from the K Jetronic and pump unit so the supply pipe was open from both sides and the return was open from engine side but was still connected to the fuel tank. My Question i blew air through the supply pipe from the engine side and no problem air was passing freely but when i tried to blow air from the return pipe engine side to tank this was not possible, is this normal or do i have a blockage ?

 

[mattkh]

I need a reminder of where the fuel pressure regulator is on the k-jet system.

Just remembered another thing. On my VW there was a tiny filter, sort of an inline thing as in a washing machine, in one of the pipes on the fuel distributor.