Having trouble replacing power steering belt

The other night, I snapped my power steering belt while doing about 60 on back-country roads at 1am. Needless to say, 5000 lbs. of MB does not take sharp curves at this speed very well without power-steering.

I got the car home and bought a belt (Actually, I got all of them, when one goes bad, the rest are sure to be close behind).

The alternator and A/C were easy to change, but I cannot seem to get the power steering pump to move. I have released the two tension adjusting bolts more than necessary, but the pump will not move. These belts were replaced about 3 years ago by my mechanic, so I know the pump moved at least once before.

Is there a trick I am missing? Anyone with insight on the 240D, W115 power steering pump would be appreciated.

Thanks in advance,

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William
76 240D - 550K miles
78 300D - 200K+ miles