It seems to be fixed now. I thoroughly cleaned the motor as best I could with 99% isopropyl, and I stole and cleaned better brushes from an old bachmann diesel. no more sparks or smoke but time will tell
Building my first layout, 4x8 contemporary urban area in HO scale
The motor can be fixed by replacing the brushes, truing and cleaning the commutator (cleaning out between the segments) and making sure the spring contacts are clean and make good contact with the back ends of the brushes.
The bad news, though, is that the motor likely got in this condition by being massively overloaded -- by resistance, or wear, or slop in the drivetrain. So much current was required that the brushes were sparking and overheating. They are carbon, so they burned, cracked and crumbled -- something observable with old overloaded diesel-electric switcher traction-motor brushes, too! -- and the resulting sparking probably significantly eroded the commutator faces. That will happen all over again when the 'rebuilt' motor is put back to be overloaded again.
It may be difficult to rework the chassis to run freely and well, but that, more than just rebuilding the motor, is essential.
Yeah, add more syrup!
I couldnt find any replacements for my 2-8-0. So i 3d printed my own in ABS. While durable enough, they eventually started to slip. Allowing the rods to do their own thing, thus allowing the drivers to bind, blah blah blah.
Its just a bad design that can only be fixed by replacing with solid axles. I did however discover that Bachmanns run real good as shelf displays.
The OP, if so inclined, could always take the shell and replace the drive with another motor/frame from another manufacturer.
PMR
I think the Shapeways Bachmann gear is for the Plus Series and I tried some, they didn’t last very long. They crumbled into pieces fairly quickly. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
If you get the motor running and ever need axles Shapeways.com makes them from what I have heard. You might find a motor on ebay. Last I heard they make them for the 4-8-4.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
I found a picture online with a Google search, I think the brushes are 2mm diameter if so try some 2mm mechanical pencil filler lead. Cut it to about 4mm long and reassemble the motor and see if it runs.
Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
It’s been over 20 years since I was into a Bachmann pancake locomotive and I can’t remember what the brushes look like. Can you post a picture of the brushes? Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
The pancake is obviously over-cooked...shoulda used more syrup.
Wayne
I checked out your video. While you have the shell off, now is a good time to replace any broken, or slipping axle shafts too. This is another of Bachmanns 'common' problems.
Unfortunately this design flaw has carried over to other manfacturers of 'multi piece' axles. Such as the 'Proto' series. However, there are parts available for some of these. For Bachmann..... good luck.
I had to make my own Bachmann replacements. Be leary of models with multi piece axles, Ive never had to replace a solid axle in 50 years. (Manufacturers take note!)
the brushes just disintegrated when I tried to clean them...
It's the brushes. Take it apart and clean the armature. There are lots of YouTubes out there that will show you how.
Google Bachmann pancake motor.
Mike.
My You Tube
I had a half dozen Bachmann Pancake Motor 4-8-4s and the wheels fell off before they had enough running time to ding the motor. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
I was running my bachmann 4-8-4 northern and I saw smoke coming out of it. I opened it up and ran it and there were bright sparks popping inside the motor! This seems very alarming and I don't know what to do. Should I try to fix it or find a replacement motor?
I recorded a video of it:
https://www.youtube.com/watch?v=1s-Ij-0X2Uk
[Edit: Link made clickable by moderator]