I broke the alternator belt on my 85 300td, car got hot for a minute before i pulled over and realized what had happened.

It is a single pulley, i pulled a double pulley from pnp yard and plan to reinstall this one, however i have doubts abot how to do it, first of all i think i had the belt on wrong to begin with because the belt was going from water pump to alternator without looping in the crank, i just realized this and now wander how am i supposed to install the pulleys and belts on the new set up.

Any help appreciated.
Ep

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W123 1985 300TD naturally aspirated