240D injection pump/ ran out of Diesel/ sat for years
 

I have a 1981 grey market 240D that was running rough, much vibration, poor acceleration, some smoke.
It sat for years, I got it started and let it run out of fuel. It sat a few more years and now I need it to run. I know, I deserve to be punished for letting a fine car go downhill but I was poor with children and a sick wife and we actually drove this little Benz many a happy mile and where proud of it almost every day.
I put a bottle of injector cleaner and 5 gal. Diesel in tank. Used hand pump to prime system, got fuel to come out of out of filter. Cranked engine with injector nuts loose. Got poor fuel delivery to injectors and none to front injector. Removed lines from pump and cranked engine with the pedal to the metal and got a little bubble of fuel to 3 pump outlets and none to front outlet. No fuel sprayed from injector pump more than 1/4" .
I have priced the pump and I am not eager to spend $1,000.00 to replace the pump. Can I rebuild the pump myself or put in a handful of o rings and make it all better? I have above average skills and a lot of patience but I want to buy all the parts at once and get the car running soon.
I don't intend to restore the car, I just need to drive it untill my truck is repaired and then trade it to a friend who will make a veggie powered Henry J rat rod out of engine and axle. Old 240d's , never die, they just get even more soulfull! I kind of hate to see the almost rust free body and engine part ways, If somone close to Carlsbad NM wants the car as is speak up now! Will trade for VW engine and title or '96 Dodge pickup transmission.
Help!

A bunch of new O-rings will not fix you Fuel Injection Pump. And, If you take it apart you will need a Caibration Stand and the Bosch Specs to get it back into order.

You could simply go to the Junk yard and get another used Fuel Injection Pump.

However, you may or may not have a problem with the Fuel Injection Pump itself. You could be having a problem with your Filters or the Fuel Supply/Lift Pump.

I would un-screw the Banjo Bolt where the Plastic Fuel Tubing goes into the Filter Housing and crank the Engine and see if you appear to be getting a good Fuel volume out of there. If not you have a Fuel Supply issue.

If it appears that you are getting a good Fuel volume out of your Fuel Supply/Lift Pump tighten the Banjo Bolt up and do the same thing but this time to the other Plastic Tube that comes off of the Fule Injection Pump to the Filter Housing. Loosen that Banjo Bolt and Crank some more to see if you are getting Fuel volume out of there. (This is The Fuel Returning from the Fuel Injection Pump.)

If that looks good tighten the Banjo Bolt and use something to clamp off the Fuel Return Hose (the Cigar Hose) that goes back to the tank (doing this will keep the Fuel Pressure supplied by the Fuel Supply Pump from being relieved so you should get max pressure). And, loosen the Fuel Injection Line Nuts at the Injectors and crank and see if you get fuel out of it now.
Or you could do the same as above but remove the Fuel Injection Lines completely to see of the Fuel shoots up out of the Fuel Injection Pump.

If after all of the above you still do not get Fuel from a few Elements I could be the Plungers in some of the Elements are stuck in the UP position due to rust or just solidified Diesel Fuel. If so let me know and I will give further instructions on what to do about that.