Here it is:
Unplug the motor from the wiring harness……in-line plug.
Remove front frame bracket (2 screws) holding gearbox to frame.
Invert chassis.
Remove 4 screws securing gearbox cover to bottom of gearbox, remove cover.
Remove gearbox/motor assembly from chassis.
Remove crankpin bolts from siderod/counterweights.
Rotate drivers as necessary to access bolts.
Remove siderods, noting how they mounted and which direction the lube cups on the siderods faced.
Block chassis, with wheels up.
Remove bottom journal retaining plates, down both sides of frame (8 machine screws per side).
Lift off retaining plates.
Lift out complete brake rigging and shoes, noting how they were mounted.
Lift out ONLY #3 (geared) driver, being careful to retain the springs in the journal recess and the plunger for pickups.
Sometimes grease will cause these to adhere to the parts as you lift them
At this point, do NOT turn the chassis over until the driver and plates are completely re-installed.
Remove counterweights on #3 driver with small Phillips screwdriver, through the retainer ring in the center of the counterweights.
Remove counterweights from axle and set aside.
Slide journals off axle, noting orientation of journals and any washers.
Slide drivers off axle.
Remove oillite bearings from axle.
If your gear is cracked, it will at this point slide off the axle by hand.
If not, I use a deep ¼” drive socket that just fits over the axle.
Place in a vise, compress the axle into the socket, and the gear will come off the axle.
At this point we have found there are at least two different axle diameters in use on Bachmann 2-8-0’s.
The gearbox was designed for the smaller axle, and you can tell by trying to fit the new gear onto either end of the axle.
If it will not go on at all, axle diameter reduction needs to be performed. There were some 2-8-0’s with slightly larger diameter axles…no idea why.
With a small flat file, remove all serrations on the axle that originally held the factory gear in place.
Hold new axle gear next to axle, note location of setscrew, and file a flat in the axle to retain the setscrew at the location determined.
Press gear onto axle to the location specified, using the deep socket if necessary that was used to press old gear off.
Locktite setscrew and install tightly, insuring the “sweet spot” is located.
Install new bearings on axle, with retaining lip in specified direction.
Install drivers onto axle.
Install journals onto axle.
Install counterweights into axles after applying a drop of 222 Locktite to tip of screw.
Compare orientation of quartering on #3 axle to that of other axles in chassis.
Install #3 axle set into chassis.
Re-install brake rigging.
Re-install journal retainers and screws.
Test-fit gearbox to chassis.
Insure gearbox is centered properly on gear and not impacting driver stubs.
You will note there is a pad for gearbox alignment in the chassis at the rear of the original and new gearbox.
Note location of said pad in relationship to new gearbox while test-fit.
We have found, so far, that a shim of # seems to be ideal, but you won’t know until the boiler is re-installed, as the forward gearbox alignment pad is the forward boiler weight.
Glue this pad to the back of the gearbox (chassis portion is curved, and difficult to get good adhesion) with something removable, like clear Silicone, Goo, or another type of contact cement.
Mount gearbox to axle.
Re-assemble siderods to drivers.
Now, we need to trim the firebox to fit the new motor.
First, remove the boiler backhead (two little bitty Phillips head screws at 9 o’clock and 3 o’clock).
Temporarily remove the firebox flicker board.
Next, remove the two screws holding the weight to the floor that were hidden by the flicker board.
Re-install the flicker board.
Remove the 4 screws holding the floor to the cab (4 corners of the floor).
Release the catches at the front of the cab wall, sticking through the floor, and separate the floor from the cab enough to remove the weight completely.
Re-assemble the floor to cab.
Using the template and measurements provided, cut the bottom of the firebox out as shown.
This is a MINIMUM cutout, and your particular installation may require minor adjustments to the edges of the cutout area.
Test fit the chassis to the boiler.
Check the movement of the motor/gearbox fore and aft with chassis fully down on boiler.
This can be done by reaching into the open backhead area and moving the end of the motor up and down, while observing the movement in the chassis.
If the shims are too thick, the motor will not “rattle”, and will not float up and down freely.
If too thin, the motor will rattle excessively.
Adjust shims to suit.
When you are certain the chassis will fully drop down onto the boiler, remove chassis, set on the wheels.
Cut the plug and wires off the old motor at the noise suppressor board.
Strip back the ends, and solder the wires to the new motor.
Plug motor into the boiler plug.
Block chassis off the workbench enough so the drivers can rotate.
Plug tender into at least the 4-wire harness from locomotive.
Lay tender on its side, apply power to the tender wheels, left and right sides.
Observe direction of drivers and headlamp/backup light.
If drivers turn in direction of lights, it is wired correctly.
If drivers rotate reverse of lights, reverse wires at motor.
Chassis will be somewhat noisy, as with no weight on drivers, flanges rub on brake rigging.
If operation is satisfactory other than the noise of the flanges, re-assemble chassis to boiler.
Once complete, fabricate new weights for firebox area.
This can be done with old lead weights from other locomotives, stacked stick-on tire weights, or any other weight of your choice.
Ideally, the locomotive should balance between #2 and #3 drivers.
We have found this unit as delivered is VERY light in the nose, and we stack several layers of stick-on tire weights in the bottom of the smokebox to help.
Silicone or double-back tape weights down both sides of the motor through the backhead, keeping weights clear of motor.
Re-install backhead.
Track test.
Note: Barry cuts the cast weight in the firebox with a bandsaw. I do not have a bandsaw, nor do most hobbysist, and I like to be able to adjust, hence the use of stick-on tyre weights.
TOC
- have a cup of salt ready, for the many times you need a grain of the stuff.