Fixing Classics/United "Voyager" Optimus shoulder
On my Dark United Optimus, one of the arms wasn't folding properly into the side of the cab in truck mode, and I couldn't work out why, as it didn't look like there should have been anything in the way. When I took a closer look at both arms (at the shoulder joint), I realised that the part that connects the arm to the chest was a millimeter out... but wondered how that was possible, since it looked like it was symmetrical, and was a fixed part with a solid pin.
I guessed that maybe the part wasn't symmetrical, and had been placed the wrong way around during construction. If that were true, it might be unfixable due to being attached to the arm with a pin.
I had to see if it could be removed from the chest, which might allow me to swivel it on the arm joint and then replace it into the chest the right way around.
It wasn't easy, but I managed to find 3 screws underneath the chest (requiring rotating the leg section into different positions to get to the screws), and it popped off the chest/arms/head section nicely.
In the photo below, the arrows point to the height of the looped parts that were different. Number 1 was the one that was too low, while Number 2 was where it was supposed to be. That mere 1 millimeter difference made it impossible to transform into truck mode without it being a deformed mess. Removing that looped bit (and the arm it was attached to) and turning it around left me with both sides being like number 2, which gave the clearance necessary in truck mode.
http://www.toycollectors.com.au/blog/423.jpg
Putting it back together was a bit of a challenge as well, because there were two little posts that had to line up inside the chest (you can see them on each side of the bottom screw-hole), and they move around because they are part of the hinged head.
So if you find yourself having trouble getting the arms of the cab lining up properly, look at the shoulder joints in robot mode to see if one is too high, and try this fix.
