W203 220CDI fuel pump leak

[Jonathan Lingham]

Car cranked but wouldn't start this morning. Tried an hour later and it started. On examining the engine I saw there was a small fuel leak from the top of the pump.

My question: how feasible is it to replace the rubber seal at the top of the lobe (assuming this is the problem) with the pump in situ? Or do I really need to take the pump off the front of the engine to do this? I know kits are available at about £15.

 

[Steve@Avantgarde]

Are you talking about the pipe that goes into the pump? Are your pipes plastic or rubber?

I would be able to tell you if you stated the year of your 203.

 

[Jonathan Lingham]

Are you talking about the pipe that goes into the pump? Are your pipes plastic or rubber?

I would be able to tell you if you stated the year of your 203.

Thanks, Steve.

I've just been out to have another look at it. It started without any problem (yesterday was the first time I'd run it for six weeks). I ran it on tick over for half an hour, to get up to temperature and to charge the battery a bit. The small leak was very much less today, nothing more than a slight weep on to kitchen roll, maybe four drops-worth during that time.

The leak seems to be coming from the joint between the head of the top lobe of the HPP. I think the connectors and pipes are all sound, so I assume it's an O-ring that's letting go. I've taken some pictures and will try to find a way to post them here.

But I think I've answered my own question! I will need to take the pump off...there's too much clutter around it to get the top of the lobe off...access to the back two star bolts isn't possible unless it's removed.

The car is a 2002 c220 cdi estate.

 

[Jonathan Lingham]

 

[Jonathan Lingham]

 

[Steve@Avantgarde]

If its not been started for 6 weeks then it would have likely needed to bleed some air out of the system that had gotten in. Any leaks from the fuel system will allow air in.

There are repair kits available for these pumps, I never fit them as you can also buy really good reconditioned units these days which outweigh the labour of striping it all to bits and rebuilding it.

I would also recommend fitting new o rings on all of the plastic pipework on the fuel system.

 

[Jonathan Lingham]

If its not been started for 6 weeks then it would have likely needed to bleed some air out of the system that had gotten in. Any leaks from the fuel system will allow air in.

There are repair kits available for these pumps, I never fit them as you can also buy really good reconditioned units these days which outweigh the labour of striping it all to bits and rebuilding it.

I would also recommend fitting new o rings on all of the plastic pipework on the fuel system.

Thanks for this advice, Steve. I've just fitted a reconditioned unit. It all went in fine, but...now it won't start. Perhaps I'm not being brave enough holding the key so that air is purged from the system. How long should this take? Or is it possible that I've managed to refit the fuel delivery and fuel return pipe the wrong way round. I'd have thought MB would have designed it so that this was impossible, but the Haynes hanual only refers to the one pipe on that side of the pump, and I failed to label them when I took them off.