For o-rings I'd use a local supplier that has Parker viton 75 o-rings. A lot of members have ordered from mcmaster but I feel a little more comfortable with Parker made ones.

In a few minutes I plan to post a new thread with info on the delivery valve part #'s and o-ring sizes. I've tried to verify they are correct but you should vet the info. More and more often I have an oldtimers moment and can't think of things I should know.

Wish they would create a 'sticky' thread or pages with the most commonly used part #'s.

The internet is your friend if you use it properly. Today I ( hopefully ) saved over $300 on parts by ordering from europe. Basically including shipping I paid for six what one would cost in the states. There are several dealer sites that discount about 25 %. I always look at pelicanparts.com and buy from them if their prices are close.

Basically I'll enter a simple search like " mercedes 0000743793 " and then click on the ones that appear to not be a questionable website. Prices vary dramatically even for reputable brands. Some sites offer a ' lifetime ' warranty on the parts they sell.

This is another informative post:

http://www.peachparts.com/shopforum/diesel-discussion/392177-whats-purpose-copper-washer-delivery-valve.html