Hello all,

As many of you have seen previously on this forum, I have a 3082 BR41 that will not run right in R1 curves (binds to the point of stopping except and excessively high speeds) no matter what I do. I've cleaned the chassis extensivily with Ronsonol (normally does the trick), strips it down and built it back up, run it with various bits of the valve gear disconnected or removed. I still am not sure what's wrong with it, although I think maybe 1 or more of the axles maybe slightly bent.

At any rate, I have a new "solution" for this problem (which worked), to replace the chassis of the locomotive. I was able to find a used chassis on eBay.de, so that became my doner. I will also keep the original chassis and maybe still one day be able to figure out what is wrong with it. In this thread I will explain how I swapped the chassis. Due to the nature of this project, I also decided to use it as an oppertunity to point out a couple of standard service items on a DCM (drum commutator motor) locomotive. I know that for many in this forum its very basic stuff, and many of you have a vast knowledge from which I have learned a lot. I thought this may be helpful for new users or members who are still starting out. I am a visual learner, so pictures always help in understanding.

Now, we progress. Steps:

Edit: Step zero is cleaning the doner chassis with ronsonal and a q-tip (or similar) to remove carbon in the motor shield area as well as any old oil gumming up the axle.

1.) Repair visible painted areas on old chassis as the had a few small flaws. I used Testors 1150 Flat red and 1103 Gloss red as needed (colours were perfect for DB red, as suggested by Dr. D.), applied with a brush carefully and employed some paint filter to hide any brush strokes. I wish I had taken some pictures of the process, but I did not. Maybe next time.

2.) Get your locomotive and new chassis.




***Edit - Updated SFCM (small flat Commutator motor) to DCM (drum commutator motor) at Brakepad and Chris' suggestion, as this is the correct motor type in this locomotive, but also many locomotives released in this era (70s/80s).***

Edited by user 20 November 2012 14:47:20(UTC)  | Reason: Not specified

4.) Now it's time to remove the locomotive brushes. You would use this same procedure to replace them. Since mine were in good shape, I just reused them. Use tweezers to pull the little copper spring that holds the brush. if you move it upwards, you can allow it to pull back against the dome on the motor shield, thus exposing the brush.



Next, remove the brushes. Sometimes you can use a small flathead screwdriver or tweezers to do this. Sometimes it's easier to pick up the locomotive and gently/carefully shake it until the brush falls out on your workbench. Note the position of the brush springs in this photo, this is where they can be "stored" to make room to get the brushes out. Note there are two brushes, one in the channel on each side of the motor.

Another shot with the wire and motor cover/field coil removed from the main chassis:

8.) Since I am just swapping the front chassis due to some sort of drive problem, I am using the same tender. The tender could also be torn down to remove or service the reverse unit, pickup shoe, etc, but we will have to save that for another day. The tender is held on to the body by a single "C" clip. I used a small flathead screwdriver to carefully pry this off until it released. There are two little cutouts in it which you can get the head of your screwdriver under.

In the photo, the C clip is already removed and laying on the cloth below the shaft. The tweezers are pointing at the shaft from which it was removed.

3.) Reinstall the motor cover and field coil. These here is the completed result (two screws installed minding the wire lug on the lower one):



4.) Route the (black) wire for the headlight along the channel in the chassis. Make sure when you get close to the motor it doesn't slip out and get between the wheel and the chassis. Also, again be mindful to keeping the valve gear in alignment. The lamp contact can simply be pushed into it's slot.

5.) The shafts of the motor should be oiled. There are many different preferences for oil, it is up to you what to choose. Just make sure to only apply a tiny bit. Too much is bad, it can contaminate the motor, get on the track, etc.

Here is where the oil should be applied on the motor shield. Give it just a moment to soak in.



Now flip the chassis over and apply at the opposite end of the rotor shaft. Another moment for soaking in.

7.) Now we will reinstall the shell. In some locos (again, such as this one), there is a clear plastic diffuser to take the light from the bulb to the headlights. They can fall out pretty easily, so make sure you have it and that it is in place.

The bottom front of the shell:



Reinstall the shell and screw it on. The screw should be hand tight, but not too tight. Make sure it is not so loose the loco will fall if you pick it up by the shell! Also, 3082 is fitted with a cover contact (part of the bulb powering mechanism) that could power a smoke generator. My loco does not have a smoke generator, but you still have to mind the copper contact when reinstalling the shell.