Originally Posted by Diesel911

I never looked at the superturbodiesl forum much. I am just happy if my Car gets me down the road in a normal manner. However, that does not mean that in some thread there may be the dimensions of the 603 Fuel Injection Pump O-rings there.

My MW Fuel Injection Pump does not use O-rings up in the Delivery Valve area so I have never had a reason to keep track of the O-ring delivery valve O-ring issues.

Another thing is I am not as I will say picky as some. Harbor Freight sells viton O-ring assortments.

If I had the 603 pump I would remove one of the leaking delivery valve holders and see if I could remove the old O-ring intact and get some sort of an idea as to the measurements and take those measurements with me to harbor freight and see what they have in their viton assortment.
If there O-rings that I thought would work I would buy the assortment and perhaps replace just that one O-ring and see if it stops the leaking (you can sometimes put an O-ring on a part and turn it in by hand and see if it snug enough to seal or too tight).

If that worked I would be inclined to do all of them and hope for a reasonable longevity.

I would be more concerned with the crush washers. They don't have to be bosch (there is other companies that make kits for Bosch Fuel Injection Pumps) but sometimes the crush washers up in the delivery valve area are a stiffer alloy then just plain copper washers. So going out and buying an assortment of copper washers might not be a good idea because the torque spec is set up to match the alloy of the crush washer used.