Both Lajo's and Rob's advice is excellent. My experience is a little different. I believe the wheels are press fit onto the axels with a small shoulder on the axel to set the gauge. I have encountered a loose wheel on a couple of occasions. When I disassemble the truck, the wheel spins freely or drops off and as a result the unit will have reduced traction and some wobble. My solution is to clean the wheel in isopropyl alcohol, slip it back on the axel pushing it against the shoulder and fasten with a very small amount of thin super glue from the outside. Remember you have to work quickly. If you "fail" and the gauge is too big, you will have to use debonder and try again. I have also encountered a wobble and upon examination have found that the plastic insert in the wheel where it attaches to the axel is "out of round". I suspect that this occurred when the loco got hung up on a turnout and the short melted the plastic insert. Unfortunately I know of no solution except to hope you can get a replacement wheel or wheel and axel assembly from MTL.
whether the engine stands up right or flops over is dependent on the spring tension in the cats whisker of phosphor bronze that collects power from the top of the truck and transfers it to each half of the metal frame holding the motor. This is the only tension item that keeps the truck centered in the gimble and if there is not enough tension the engine can flop from side to side as it goes in and out or corner sor curves and can even flop over on it side falling off the track. When the tension is correct it is hard to set the truck in the frame when reassembling the engine and when it is too slack it is very easy to assemble the engine chassis but as soon as you set it down on the table top you can see that it leans to one one side, or the other. To reset the whisker I pull it out of the chassis and straighten it with flat face or jaw needle nose pliers and then pull it back into the chassis into the hole it was remove from. When you assemble the two halves of the frame without the trucks these whiskers should almost touch. I tend to use a piece of 1/16th thick styrene as a gauge. It needs to pass between the whiskers without bending or deflecting them, then they are good to go.
Paul Lynde would have told you not to let the loco drink so much, but I doubt that answer would have helped much...... ) I think Garth nailed it pretty squarely on the head. What he said makes sense. Lindley also has a good point. Gook luck with your repairs. I think you will eventually get it right.
I have had that same problem with the wobble, but we have learned to live with it if we want to run them. Unfortunately none of us are handy enough to do the repairs as Garth points out. Wish we could though. I do have a question on the B units though. Is it possible to lighten them up so they will be easier to pull? Is it possible to put different trucks on them or remove the existing wheels and put others on?
lightening them does not improve them but the trucks can be modified to relieve some of the friction and they will roll better but i have never been able to get them to run free so I opted for modifying the shell to fit over a powered chassis and so my b units are no longer being dragged around. cheers Garth
