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671 Repair Questions - 1946 turbine

I have a 671 steamer which I believe to be from 1946. It is almost completely torn down for cleaning and lube, except for the motor and frame; the motor retains the armature, both armature bushings and the pinion (drive) gear, while the frame still holds the drive assembly (wheels and axles.)

Below are the questions I have regarding the cleaning/adjusting of the motor assembly and the drive assembly. BTW, the commutator is now clean and shiny and perfectly flat; no cupping, no segment-to-segment wear patterns.

  1. Identify year? I believe mine is a 1946: it has 6 nickel-rim tires, a horizontal motor that employs an armature pinion gear to engage the double worm drive shaft; it has a horizontal e-unit, and has a lamp style smoke unit
  2. Sleeve bushings or ball bearings? As near as I can tell, mine appears to be a 2020M-1 motor & pinon assy, and has only two internal brass bushings to support the armature. I cannot see any e-clips on the armature shaft that would suggest ball bearings are being used, and if tey were there, they would be inaccessible due to the fact that the pinion gear is very close to the motor casting. The armature shaft has at the front end, a brass pinion gear (not a worm type) that engages another similar spur type gear on the double worm drive shaft – this appears to agree with Greenberg’s info for 1946, although Greenberg does not actually show a picture of the double worm drive shaft, nor does he list a part number - did I miss it???
  3. Armature End Play – relevant or not on my pinion gear motor? I would think less so as end play in this scenario is much more forgiving with regard to aligning the pinion gear with the drive shaft spur gear (no worms involved at this stage.) FWIW, my armature end play is 0.020" (exceeds the recommended 0.010" for ball-bearing equipped motors) and does not appear to be a factor since the main pinion gear is 15/64" thick and the gear it mates to is 8/64" thick, meaning there is 100% meshing of gear teeth at all times, regardless of the current position of the armature shaft, be it full forward or fully aft.
  4. How to remove the main pinion (drive) gear on the armature to replace the armatures bushings? Right now, the side play on the armature shaft is quite minimal, so little that I don’t really want to disassemble things just to clean and lube it. Should I decide at some point that it is necessary:
    1. What is the best way to remove, then reinstall this gear?
    2. Is there any special tooling? I do have an arbor press and wheel puller, but not sure the wheel puller can pull this smallish gear, it’s meant for engine wheels.
  5. How to replace both brass bushings?
    1. Removal - Specialized tooling? A skinny long punch and a hammer?
    2. Installing - How to seat new ones? Hopefully not a fatter long punch and a hammer!
  6. Wheel Spacing – do you have any specs on wheel spacing and allowable end play in the wheel axles?


I am using Greenberg’s manual, but his explanations don’t always take into account this earliest version. For example, on pg 65, 3rd paragraph down it reads, “When replacing the motor armature, be sure to assemble the thrust ball bearings properly.” I don’t believe the 1946 has any ball bearings in/on the armature, only two thrust ball bearings located within the bearing blocks on either end of the double worm drive shaft. Am I right or wrong?

The rear most worm gear on the rear axle is worn and needs replacement, which brings up drive wheel spacing – I have the tools to replace this gear, but I lack any authoritative info on how wide the wheels should be spaced. Their current positions (haven’t pulled any wheels just yet) look good as far as wear patterns on the wheels, but the rear left drive wheel rubs on the frame, and the front left drive wheel has a cam pin on the inside of the wheel which smacks the frame every time around, although I’m fairly certain that will go away when I reinstall the cam lever and flapper assy for the smoke unit. But at the least, I will have to pull the rearmost driver and the blind drive wheel in front of it, and short of any real specifications, will have to use existing measurements that I have taken, measurements which are clearly affected by the nickel rim tires, at least on the flanged wheels.

I have read many of the previous threads on this forum dealing with repair issues on the 671, but did not see a whole lot of discussion aimed directly at the 1946 version. If you own a 1946 and have disassembled yours to this point, I would appreciate hearing your experiences and providing answers to the above questions? A lot to ask, I know, but I would appreciate any and all first person experiences.


Thank you!



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