Don't bother rebuilding the booster cause you don't get what goes bad regarding holding vacuum in the rebuild kit. Only the dealer has the booster rebuild. They cost under $10 and are stocked in Germany since no one here seems to rebuild them. Go to a wrecking yard with your Mityvac and test one there and see that it holds steady for a while. You'll get real tired pumping down the rbooster but it's better to do that before removing/installing and...after that remove the master cylinder to check that it was not to badly contaminated with brake fluid. Once approved crawl under the driver side dash, and fumble around with the booster bolts (it's a real pain to unbolt but it goes pretty quick). Should cost $50 or less.

You can rebuild the vacuum pump with parts from Fastlane but a new pump is a better guarantee and you need to build a simple wood jig if you rebuild it yourself. Don't need a new rocker unless yours is bad (need to remove the pump to view). It could be a disaster for your engine if the rocker broke apart in there though. Don't forget to order a mounting gasket if you decide to rebuild. The mounting gasket holds in place with a little grease.

No need to remove the radiator. But do slip in a piece of cardboard to protect it while yoiu are removing the fan. Remove the screws from the fan with a ratcheting box wrench (no room for a socket) or spend 15-20 minutes slowly removing with a plain box wrench. Don't remove the last screw, just loosen it.

Good luck

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1972 450SL
1982 300D Turbo