Master builders cut scene
You can find this crossed out scene on page 23 of this scan of the Master Builder's script.
By Herb Engelhardt and David N. Gottlieb
On Bonecrusher
The giant bulldozer is knocking over large sandstone outcroppings from the ground that jut out near the foundation. Scrapper joins him into shot, transforms to his payloader mode, and helps move the mountains of rubble.
On Scavenger
With his massive power shovel, Scavenger digs amazing deep radiating trenches (Like canals) that will accommodate the foundation. The camera pans along one of these trenches to reveal Hook manipulating giant forms.
Suddenly the canals and forms are inundated with what looks like a tidal wave of molten steel! The camera tilts up to reveal Mixmaster mixing the steel in its cauldron while simultaneously pouring out a river of the molten stuff into the forms below.
On Hook
He climbs out of the trench then scales the beginning girders of the structure. He transforms into truck crane mode on the lower floor.
On Mixmaster
Now he turns his spout and pause more molten steel into huge modular molds on the ground. Suddenly out of nowhere a hook descends and picks up one of these molds.