Delivery Valve Seals Replacement: Problems, Cautions, and Tips?
 

I've always had my indie replace delivery valve seals (the two times I've had to have it done). Thinking about trying it myself on the 87 300TD I just acquired...indie even offered to lend me the tool I'd need.

I see a nice DIY for the 606:

http://www.peachparts.com/Wikka/OM606DeliveryValveSeals

I imagine 603 would be similar. However, when I read various threads, it seems that, as often as not, this is a job where people run into trouble, mess things up. So I'm tempted to play it safe and just have the indie do it.

I'd be glad to benefit from what any others have learned from experience. Thanks.

From what I have read it has been kind of hard to pick out what people have done wrong.
I suspect 2 possible issues.
One is the actual Delivery Valve; 2 pieces the Valve in the Center and the outer Body. The Valve can only go on one side of the Body and there is a band machined into the Body so you can tell which way it was supposed to go.
But, if you remove it you have to watch which way it came out and Write it down or take a picture.

The other issues seems to be that somehow people are managing to pull up the Barrel of the Element up and out of the alighment Slot/Pin.
That can happen if you pull up on the outer barrel of the Delivery Valve, use a Magnet on the Delivery Valve or rotate the Fuel Injection Pump with the Delivery Valve Holder removed.
Depending on the position of the Fuel Injection Pump it might also happen if you jarred the Pump hard on the work Bench.

If you are working with the IP still on the Engine I would resist the temptation to remove all of the Delivery Valve Holder at one time and try to replace only one Crush Washer and O-ring at a time.

Screw the Delivery Valve Holder down by hand (if you lube the O-ring you should have no issues screwing it in) and before yout Torque it lay a staright edge acrossed the tops of the Delivery Valve to see if the one you worked on is sticking up higher than the others.

If it is sticking up a lot higher then you know you have a problem inside.

I think most people get in trouble pulling too much out and then not getting everything back in correctly as D911 pointed out. The spring will fall out half the time when the holder is lifted off and sometimes the valve needs to come out in order to get to the crush washer. Other times it will be up inside the holder. Nothing other than the oring and crush washer *have* to come out to complete the job.

I'd start, and stay, much cleaner than is shown in the DYI you linked. Dirt and grit is not your friend inside the IP/DV's. Multiple rinse cups of D2 (dirty, clean, and cleaner rinse solutions) help get rid of oring and other debris.