I have very hazey recollections of this film but me and my younger siblings all remember seeing a film in the late 80's I guess,where it was set on some kind of creek or quary! There were kids in the film who I think rode bikes with flags on them. I can remember some kind of shed being involved in the story line too but I distinctly remember some crane or some kind of machinery coming out of this creek/water! Pleeeaase help!

I think that is
THE QUEST with Henry Thomas. At least sounds just like it.

WOW!
I remember that movie. There's an old crane under the water and the air leaking up from the bottom of the pond fills the crane bucket up every so often and the bucket floats to the top of the pond and looks like a monster. The kid investagates and gets traped under the bucket. That's a heck of a memory Lunarblue.

It was one of those movies that my family remembered but couldn't name and had to go to my mom's to get the tape.

But thank you.