Fuel pump 350SL

Hello, I have decided to change some fuel parts. After disassembling fuel pump I found a spring and a little ball in the hose which goes from fuel filter. The spring seems to be half way out, a photo attached. I guess this is not normal, isn't it? Can it be fixed somehow? The pump has been working before disassembling. 
Thanks&regards,

Dodi
350SL '72
 

Hi,
you found parts of the valve that hinders fuel-flow-back, the non-return-check-valve that is part of the pump.
Now - the valve is not functional anymore - fuel pressure gets lost very fast after engine-shut-off.

You could replace the valve by an external one, like this <just an example> www.ebay.de/itm/353539487622?hash=item52...6:g:WNEAAOSwRldgzIVC

Regards
Norbert

Hello, thank you for your reply.
Could you please give me more information on this. The pump was working before taking out of the car, at least I think because I had no issue with the car. How could this happen?

In order to replace the valve, do I have to take out the spring and the ball from the pump and after connect a new valve?
Thanks.

Dodi

Hi Dodi,

inside the flange of the pump there is a mechanical limiter for spring and ball. When this breaks, ball and spring flow out and no longer work as retain valve. That means that pump will still work but pressure in ring line in engine will drop immediately after shut-off of engine. That means that starting engine will take longer as ring line needs to be refilled with fuel first.

As we do not have new retain valves available, we use an external valve instead.

I just took a closer look on the pump. There is a hexagon nut on the non return check valve so plese ignore ma second question. The nut seems to be difficult to remove, in worst case scenario it might brake, so I am thinking of buying a new pump, taking into account age of the old one. Could you recommend any available for a D jetronic?

Thanks&regards,

Dodi

Hi,

best solution is to keep old pump and install a non-return valve.