I don't remember where I read that a 617 relief valve can be used in a 603, and might be an enhancement since it's adjustable. I also remember reading that it's NLA form MB. I've never done it. Relief valve is 601 070 01 46 (list $70!) with crush washers N 007603 012112. The 617 relief valve lists for $40. Oddly, I don't see a relief valve call out for the 240D. EPC shows a hose and washers but no banjo bolt. Hmm...

Sixto
87 300D