I need to replace the universal joint at the end(s) of the two truck Shay cylinder set. Since the part is not available from Bachmann, I plan to remove an undamaged u-joint from another parts Shay and replace the damaged u-joint on a good Shay. How do I remove and replace the u-joints on the Shay assembly?
To disassemble the cylinder assembly, remove the two screws that are used with the twists that secure the assembly to the loco frame. These are longish screws, on the lower part of the assembly facing the inside of the loco when the cylinder assembly is installed in the loco. Remove the three screws of the ‘retaining bar’ (which I think is part of the chuff signal) at the top of the inside of the assembly. Remove the side covers (two pieces of square plastic); there is a 3rd cover on the center cylinder–these covers only go one way and are snap-in. The assembly will separate (watch the round cylinder covers on the top) and the u-joint assembly can be removed. Make a note of how the retaining rods (small pieces that hold the piston rod in place) are placed as these will come out. Replacement is the reverse of removal–once out, it’s pretty obvious how it goes back in.
(The entire cylinder assembly is available from Bachmann.)