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Loco Repairs – Motor Swap Out Bachmann Class 47 (OO Scale 1:76 Model) Part One

Loco Repairs – Motor Swap Out Bachmann Class 47 (OO Scale 1:76 Model) Part One

Loco Repairs – Motor Swap Out Bachmann Class 47 (OO Scale 1:76 Model)

In this article we take a look at how to swap out a faulty motor on a Bachmann class 47 locomotive model. But first what led to finding out the loco has a faulty motor. Over the last month a clicking grinding noise started to be come apparent & get louder every time the loco was run. An inspection of the wheels, axles, gear towers, drive shafts found everything to be in order & free moving as it should be. With the drive shafts disconnected from the motor, the motor was powered up & run for a while in both directions. It was quickly noted that at one end of the motor was making a grinding noise.

So it was decided to replace the motor with a new one, with the old motor being saved for a time when I can take a look at trying to fix it. So just how do you take a Bachmann Class 47 model apart to replace the motor? So with a quick phone call to Bachmann service department a replacement motor duly arrived a couple days later, it was time to get started. Let us take a look at how it’s done.

Body removal

First job is to remove the loco body. The body is held in place by six screws as shown in the photo on the right, each screw location circled in the photo. The body is also held in place by four clips too.

To access the screw holes you’ll need to swing the bogies to one side as shown on the right. The front screw (the silver one) is a little more awkward to get at as it’s under the front bogie.


Having unscrewed the body, put the screws to one side for safe keeping. Next job is to un-clip the body. The first time you do this it can be a little of the stiff side to release the body so just take your time. Carefully prize the body sides outwards a little as shown on the right. Then insert some stiff card in between the body shell & the chassis. Do this on the two locations as shown & repeat at the other end of the loco also.

The body clips on to two recesses on the inside below the cabside windows. With the card pieces now in place between the clips & the chassis, carefully pull the body upwards. It’s best to hold the bogies as you could accidentally pull the fuel tanks/battery box off.




Make a note which way the body sits on the chassis for when you refit it later on. Note the roof fan end sits over the part of the chassis that has the recess for a speaker. The orange arrows mark & show where the body clips are.



Now unscrew the two small screws circled on the right to release the PCB board.



Where the DCC deocoder / blanking plug is, you’ll see the motor left & right PCB terminals. This is where the orange & grey wires from the motor attach. Make a not which colour wire fits which of the two holes. Carefully pull the black plastic sleeve off to reveal the wire. Repeat with the other side as shown in the second photo on the right.

Next remove the four plastic sleeves as shown on the right. This is so we can release the pick up wires from the bogies.

Having unscrewed the PCB board two screws earlier, lift up the PCB slightly. Carefully pull the orange & grey motor wires free form the PCB board as shown on the right.

In Part two we’ll look at releasing the old motor from the chassis & refitting & reassembling the model.

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