Help w/ jammed bridge in cistern

[lunarxplosion]

Hey guys,
I've run into an error/am just not smart enough to figure out how to proceed with the jammed bridge on the right in the cistern, the one leading to the morgue.
In the control room, I've adjusted the weights, heard the machines starting to run, adjusted the levers so they are now stuck in place, and put all three pipes up against the wall. I figured I was done, so exited and pulled the right lever. However, the bridge is still not lowering even halfway.
I've tried throwing some rocks at it, however it's pointless since the bridge is still way up at the top. Did I miss something?
It'd be great if you could help out, thanks a lot