# Bachmann Spectrum 4-4-0 drive gear questions



## digger (Jan 2, 2008)

I have a Spectrum Eureka & Palisade model that has been the "Pride of the Fleet" until two weeks ago, during our major annual open house. It has typically hauled 4-5 LGB passenger cars around our layout with 4% grades, no problem. But during that big event, it suddenly couldn't pull itself up the hill. I could hear the motor whining, but apparently some thing was slipping. Back at the workbench, I've narrowed the problem down to the main drive gear slipping on its axle. My question is, how in the heck does one get the gearbox/driver/axle assembly out to go to work on it? With the valve gear linkage, cams, etc, I just don't see how to remove it short of half-way destroying the thing. I'm sure that someone smarter than me has had this same problem and figured out how to get the job done. Help!


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## East Broad Top (Dec 29, 2007)

Pull the caps off the drivers. That will reveal the screw that holds the wheels on the axles. (This, after you remove the drive rods.) Remove the drivers. 

Next, remove the retaining plate on the bottom that holds the rear two axles in place. 

Next, lift the drive axle from the frame. I don't remember if there are springs or not, so just be mindful that there may be. Pull off the bearing blocks, being careful to remember which side is "out." Now, get some tape, a clamp, wire tie, or _something_ to bind all the valve gear on each side of the motor together. Then carefully remove the valve gear from each side. 

You're now free to pull the motor and gearbox for repairs. 

If the gear is just slipping on the axle and not split all the way through to the edge, you can take some 3/8" ID brass tubing and cut a narrow sleeve to go around the hub of the gear, then replace the gear onto the axle. (A little JB Weld helps make sure it stays put.) If it's cracked all the way through, you have a few options. 

First, count the teeth on the gears. If it's 24, order the NWSL replacement gear (Part #2223-6). That's their "4-4-0/2-6-0 replacement gear." Problem is, I've yet to encounter a 4-4-0 or 2-6-0 that has a 24-tooth gear. All the ones I've taken apart (a half dozen or so) have been 25-tooth gears--the same as what's in the B'mann 2-8-0. _That_ NWSL replacement gear is part #2226-6. Or, you can order one of the Bachmann 2-8-0 replacement gear/axle combinations that has the brass gear. Gently heat the gear and axle to remove the brass gear from the 2-8-0 axle and then place it on the 4-4-0 axle instead. You save $3 on the gear, but you're paying $5 for shipping minimum. Don't know what NWSL's shipping is. Personally, I'd just go with the NWSL gear. They seem to be pretty robust in their own right. 

Once the gearbox is re-assembled (remember to add lots and lots of gear grease), carefully re-insert each side of the axle into the valve gear "bundles." Then replace the bearing block, being careful that "out" faces out, replace the drivers, and put the drive rods back on. You should be good to go at that point. 

Later, 

K


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## digger (Jan 2, 2008)

Thanks, Kevin! With the tips you supplied and more via PM from Peter Bunce, I think I know how to proceed. Just ordered a replacement gear from NWSL, and as soon as that arrives, I'll set aside some "quality time" and get this puppy back into service.


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## BarrysBigTrains (Sep 4, 2008)

I don't know why it helps, but I was told to remember that the valving is out to each other 180 degrees. 

And I didn't understand that until I was in the middle of the reassembly, and somehow it helped. I have done this more than thrice. 

Barry


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