1973 Mercedes Benz 450sl Water pump

I would replace the pump, and I would NOT get a generic water pump replacement from the local auto parts. MB has very strict quality standards that all parts sold through them must meet. Yes, you will spend at least twice as much for an original OEM part as you would for a rebuilt from Billy Bob's House o' Pumps, but when you replace it you'll realize this isn't a job you want to revisit. My 33 year old, 175,000 mile car is still on the original water pump, and that's what you'll want for yours after you dig into this job.