BenzWorld Junior Member
Date registered: Apr 2005
Vehicle: 1966 250SE Coupe
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Rebuilding the early electric fuel injection pumps
Thought I'd share this incase others could benefit.
I've got a '66 250se Coupe that still has its original "big" electric fuel pump. The previous owner was selling the car because it wouldn't run more than 30min and then would die and not restart unless it was left sitting for hours. None of the shops he took it too could find the fault.
I discovered there is a screen inside the intake fitting on the fuel pump. The screen in this pump was packed about 1/2" deep with rust and crud from the fuel tank. I cleaned out the crud and haven't had a problem in 13 years. None of the manuals, or parts diagrams showed this screen by the way.
Fast forward to last week when the pump started leaking out of the little pipe on the side of the lower housing. I figured this was some sort of fuel vent designed to vent fuel if the pump had an internal seal failure, in order to keep fuel from getting up into the electric motor.
With new pumps running $325-$525, I decided I'd attempt repairing it.
I took the pump completely apart, replaced one tiny o-ring about 6mm in diameter and it is back working good as new. Spent a total of $3.90 on o-rings.