Purchased a nice 1989 560SEL from a family that had owned for 10 years. Drove home 160 miles, mostly interstate. Did great!

Noticed a groaning noise sometimes at mid speed but would stop if i pressed harder on accelerator pedal. I assumed it was water pump stating to fail, but temp never rose and i made it home safe.

Next day i drove about 20 miles, and 6 miles away from home, she stranded me!

Events:
- Driving 45mph, all lights lit up on dash. Pulled over and turned off quick.
- Popped hood, discovered alternator belt was chewed and gone. closer inspection showed the water pump pulley had shifted forward(toward radiator) and was clashing with the crankshaft pulley.
- thus binding on alternator belt, and twisting the A/C belt around and knocking off on the others…
-called AAA and took a flatbed ride back to my driveway..

This was a week ago and i have been searching for an answer!

My question is… is it possible for the pulley to shift forward because of a failed water pump? Am in the the right direction? No leaks or signs before hand, except noise(could be something else!)

At this point i will need a new water pump, water pump pulley, crank shaft pulley and belts…

Please let me know any other possibilities you can think of!

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1986 300SDL ~300,000 mi.
1989 560SEL ~175,000 mi.
2011 F-150 ~37,000 mi.
1953 M38A1