I have a JCL Lionel GG1, the Congressional version, that was suffering from zinc rot in the truck frames. I purchased a replacement set of frames from Hennings and proceeded to install them.
During the disassembly, I noticed that both driver trucks seemed bound up and wouldn’t turn. I removed the truck from the chassis and I could barely get the wheels to turn. The gears were clean and meshing correctly but the wheels just didn’t want to turn.
I used a wheel puller and removed one set of wheels and the axle. The wheels now turned effortlessly. It seems the one axle was pressed against the bronze bearing sleeve in the truck casting. This was true for both power trucks. I reset the clearance so the problem axle would turn but this made the wheel gauge too wide. I ended up pressing the bearings inward and achieving the needed clearance and proper gauge.
The engine runs fine now. I was wondering if anyone else has encountered the issue with the bound up drivers. The Hennings frames look fine and basic replacement was simple.