two bridges in the cistern

[latestsaint]

i am having problems with the second bridge in the cistern, and i am almost to the point where i am thinking there is a glitch in my game. regardless, i used the walkthrough to make sure i was doing everything right, but cannot get the second bridge to lower.

in the control room i have matched the weights, and inserted the giant piston in the big machine room. i was weary of whether or not i had all the pipes tho. i installed three into the wall n the last room (which is all the walkthrough says you need), and there a flashback that asked me "what are you doing?" every time i have redone it.

but when i return to the cistern entrance, and try to use the lever to lower the second bridge, nothing happens. the lever just reloads. any idea on what im doin wrong or is my game completely botched. (i dont know if i want to start from the beginning again

i am going to check some other walkthroughs for answers, but any help is appreciated.