Here you can find some exploded service pics of the bosch VE pump, They may not be the exact part number matches, but they may be helpfull.

http://home.comcast.net/~vwgtd/vepump.htm

many thanks !!!

Be very cautious when opening the pump, I know someone who tried to fix a similar pump on a Ford, when he unbolted the cover all of the parts inside shot out & spread themselves all over his garage floor. He never did work out how they all fitted back in.

According to Bosch distributor pump for BMW

First you want to check the main shaft of the pump if there is a wear

also you want to check the housing of pump for wearing.

IF every thing ok you must to fix a seal with the same no. as Bosch said , because ifyou fix a new seal but not same no.the pump willleak again

Is theire also a way to overhaul / repair the EDC module inside the pump.

The EDC module seems to be some kind of mechanisme that controls the opening and closing times of the high pressure valves.

By this way the amount of gasoline per time unit is controled.