This wing had a leaky fuel tank problem. When removing some fabric, we found lots of missing nails, cracked ribs and other problems. All fabric was removed and the spars were found to have serious dog-legs in them : They were never trammeled properly. Because of the crooked spar, the original rebuilder did this to the central aileron hinge to make it fit! They added almost 3/8" worth of shims and pop-riveted it back together.
This was done by a licensed A&P. The owner reported an odd behavior in flight whenever the the stick was moved past a certain point: this was the aileron popping up and down as it went over-center due to the crooked hinge alignment. All fixed now, but it shows that even good looking rebuilds may hide serious flaws.