Hollander Interchange and Interchange Inc., both publish a catalog (printed and electronic), that lists interchangable parts for most all vehicles. They are not cheap (~$450) and are fairly jealously gaurded. Because of the cost, they are usually only found at wrecker's yards and larger parts places (old school legit; real countermen) not at McParts type places.

Perhaps you can finagle someone who has access to these to give you a look, as wolf_walker suggested.

Your era 300SD had Bendix and/or Teves brake parts; and Vickers or ZF power steering parts, so the manufacturer name is important for you.

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The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)