Wanted 300D fuel pump expert

[aal]

I am a new mercerdes owner, I am surprised to be told that the fix for a leaking fuel pump is replacement (£600+).
Are these impossible to fix? Is there anyone out there with the knowledge and willing to pass on advice (other then replace it!).
Please if you read this and you know the answer take the time to reply, you never know I may have the answer to your problem one day.
Cheers
1991 300D W124

 

[Dieselman]

Depending on why the pump is leaking will dictate whether it is cost effective to fix it.

The pump has an external lift pump and six internal high pressure pumping elements fed from a common fuel gallery.
The leak off pressure is controlled by the leak off banjo bolt.

The camshaft inside the pump is lubricated by engine oil fed from the engine block.

Firstly decide whether the pump is leaking oil or diesel, then where from. If the pump is leaking diesel from the input shaft then diesel is getting past the pumping pistons and the pump must be very worn. This is unlikley.

More likley the pump is leaking from one of the high pressure outlets, either at the union to the injector pipe or where the outlet screws into the pump body. If it's the injector pipe connection then just tighten it a bit, if it's the union to the body then this will need dealing with at an diesel injection specialist as the pumping volume is set by these valves.

In a nutshell unless the pump is very worn or the body is cracked, both unlikley, then a repair is a simple job.

Check ALL the diesel pipes and unions before doing anything to the pump as one of those may be the cause.

 

[aal]

Thank you

Thanks for the advice, I was able to identify the leaking part using the on line manual http://mb.braingears.com/124_DISC1/Program/matrix.htm.
The pressure maintaining valves need new seals (£7) and the main dealer has agreed a free of charge tool loan, so things are looking good.