This instructable will show you the step by step process of how to build a custom mod to control the swing on the Lego 8294 excavator. It is quite simple. Bear with me, as this is only my second instructable.
Step 1: Disassembly
Refer to the second picture for a good look at what to take off during the disassembly process.
Step 2: Materials
The picture has them all. The V-shaped connector brick should be one that has no angle. I just used what pieces I could find.
Step 3: Assembly of the Whole Mechanism
Put the longest bar in a connector, put a 2 stud bar to connect both connectors, add the 4 stud long bar, and attach the gear.*
*Note: During assembly process, you may need to put it on it by taking it apart/dividing it into 2 or 3 sections to install it easier. I even had to take the 4 pins out that hold the whole house of the machine to the base to put it on.
The second picture is of a bracket that the axel of the mechanism must go through.
Step 4: Attaching the Bracket
All you have to do it install it between those two bars as shown.
Step 5: Attaching the Shaft
I apologize for the blurry picture. I will use the image note bar to outline what has been added on.
It has all been put together. I actually had to remove the top of the excavator from the bottom in order to get the whole thing on. Remember to slide the gear up the shaft a bit for clearance of other things below.
Step 6: Reassembly
Pic.1 Attach these pieces back the way they came, minus the warning light (far left) which should be on top of the cab with the shaft attached to it.
Pic. 2 The finished product.