Originally Posted by Hit Man X

I simply removed it on my '90. Went to the '86-89 M103 brackets, it all bolts up. You just need the '86-89 fan bearing bracket and of course the alt bracket itself. I did the extra to just tidy up the engine bay.

You could always just remove the air pump and short belt it.

I believe it is an attempt to help with excessive cold start emissions (quicker converter light off, my F150 had this along with most Small Fords of the era), don't forget MB also added EGR on the '90+ cars...