Anybody out there still running their 2011 (DCC) Bachmann Doodlebug?

[delamaize]

I'm curious about the mechanics of this. If the plastic gear sleeve is cracked, but the gear itself is intact, where does the thump-thump-thump noise come from? I would think that the axle tips would slip inside of the cracked sleeve and simply stop spinning...?

-Mark

What I have been told is it stretches' the plastic between the teeth on the ones where the sleeve is cracked, but the teeth are not. if there is any truth to it, I'm not sure, but it sounded good to me.
I'm still a firm believer in just repowering it, using the method that I posted from Randgust. It only took me like an hour or two to do the modifications, and get it back on the rails. Why band aid fix it, when you can fix it for good, AND get all wheel drive.

[spookshow]

Once again, I am not interested in performing your chassis replacement fix.

-Mark

[peteski]

I'm curious about the mechanics of this. If the plastic gear sleeve is cracked, but the gear itself is intact, where does the thump-thump-thump noise come from? I would think that the axle tips would slip inside of the cracked sleeve and simply stop spinning...?

-Mark

No, the crack almost all the time extends to into the gear.  But when the sleeve is installed on the axle sleeve, it also closes up the crack on the gear, and since the crack will not reopen, the gear will also remain usable.

[brill27mcb]

The gear and the sleeve(s) are one and the same piece. You will see the crack running through a trough between two gear teeth.

Rich K.

[robert3985]

Although not a sure fix for old, hardly-ever-run motive power, I've found that on some of my old engines that have sat in their boxes for over twenty years, that the grease has hardened up in many of them, not only making starting at all difficult, but after they get running, they thump around because the hard grease has settled in mainly one place somewhere in the gear train.

I started using a hair dryer to heat 'em up a bit...like just below not being able to hold on to them with my bare fingers...pointing the hair dryer at the bottom of the engine to heat mainly the trucks and chassis.  Interestingly, this softened the hardened grease quite a bit and the vast majority of them ran pretty well afterwards...except some needed gear-train cleaning and re-lubing.

Might want to give this a try before assuming it's a cracked gear that's causing the problem.

Cheerio!
Bob Gilmore

[spookshow]

It's definitely cracked gears - I can see the cracks.

-Mark

[spookshow]

It's sounding like James and his FUD gears aren't going to be an option, so I think I'm just going to backburner this one for now. Who knows? Maybe Bachmann will come out with a third run with better gears before I kick. In the meantime, they can go back to looking pretty in my display case 





-Mark

[Lemosteam]

@spookshow ,

Leave it on the back burner for a bit.  I have my D-bug out for a different project, but I might pull it ahead if mine is cracked too.  In my solution, I would design the gear to have brass/aluminum tubes installed on the gear prior to reinstalling the shafts, and I would design it to fit off the shelf tubing dimensions, so no tube slice/soldering as in @peteski 's images.  The newer ABS like resins can handle a lot more stress/wear than the FUD of old.

[spookshow]

Sounds promising! Keep us in the loop 

-Mark

[dem34]

Eh. Its a doodlebug. Thats just the ambiance.

Yeah, all 4 of mine have cracked gears. Doesn't really seem to effect them a whole lot besides running noise, so they only get brought out as Greeneberg show novelties.