AF 21155,. Docksider

Long time since I worked on one of these but I seem to remember that the problem is because the worm is too high on the armature shaft. You need to tease it down a bit more to get the commutator alignment correct.

This means taking the bottom assembly off, be careful about the contact strips pinging out.

Based on your picture the armature does appear to be sitting low, it is not centered in the field as it should be. There is no serrated brass washer in the blowup diagram or parts list. A Fibre Washer is shown on the commutator end of the mount but not on the worm gear side. I will add a dimensioned picture of the armature so you have it. I have never taken mine apart so unfortunately I do not have any first hand experience to offer.

@AmFlyer posted:

Based on your picture the armature does appear to be sitting low, it is not centered in the field as it should be. There is no serrated brass washer in the blowup diagram or parts list. A Fibre Washer is shown on the commutator end of the mount but not on the worm gear side. I will add a dimensioned picture of the armature so you have it. I have never taken mine apart so unfortunately I do not have any first hand experience to offer.

That doesn’t look like the armature I have in my docksider. Mine has a nylon/plastic worm which pushed onto the shaft as I remember.

Did they make two different armatures?

Thanks, my worm is plastic too and i dont know how to change the height.  This engine has been ‘worked’ before so I dont know the history.  I can try to move the worm down a bit.  Anyone know best way to do that.  Ive had the bottom plate off but could not move the armature up or down very much.  Thanks for the replies.

The motor documentation does not show any nylon or plastic worm gears, all are metal. There is a different armature for the 21158 Docksider, but it is sized differently. Easiest way to confirm is the resistance. The 21155 should measure 1.7 ohms, the 21158 will be about 3.5 ohms. Here is the 21158 armature.

Looking at the 21158 specific parts, it uses a wheel axle and driven gear assembly. There is no worm gear listed for the 21158 yet one is clearly required. That could be the source of the nylon worm.

We have been out for the evening so I am playing catch up now. I can’t remember which engine I was working on but it wasn’t the blue one.

I am trying to remember exactly what I did to move the worm down the shaft and I believe what I did was to put a flat bladed screwdriver on the underside of the laminations which has a black plastic insulator and wedge it against the chassis and lever up the armature which effectively shifts the worm gear down the armature shaft.  Just be mind full that you don’t have to move it much and check for alignment after each small movement.

These are really cheap and cheerful engines and the engineering for them is pretty poor.

Here is the parts diagram for the docksiders. The worm is number 23. The Gilbert part number is PA15A224

Thanks,  I managed to remove the armature and guess what?  There is another star(serrated)  type washer on the bottom end holding that bearing and fiber washer.  So the washer installed in my top end is duplicated at the bottom of the armature.  Neither washer is shown on the parts diagrams!  I did remove the worm gear and reinstalled but now the gears aren't meshing at all so I have to disassemble and try again.  Hardly worth the time on this engine!  I will use an appropriate tool to press in the top washer so the armature will at least not wobble.  Hopefully that may fix the problem.  That contact plate on the bottom is a real pain to have to reinstall!  The rest is easy.  I can only assume that AF built these like this from the factory.  Maybe it is a latter version with the nylon worm gear.  They just never updated the diagrams.  

Thanks for all the info.  OGR Forum to the rescue again!

Ukaflyer, I looked at that diagram several times and missed the worm. Maybe I need better reading glasses.

@AmFlyer posted:

Ukaflyer, I looked at that diagram several times and missed the worm. Maybe I need better reading glasses.

Yeh, it can easily be missed. The parts list makes it easier to identify. The method of holding the two bearings in place is really an odd way of doing it. It sounds like the OP hasn’t got the bottom bearing secured properly with that locking washer if he can’t get the worm to mesh again.

Gilbert certainly had some funny engineering methods in doing things.

Ok, third try, staked the star washer to the top of the brush plate after inserting the fiber washer and bearing.  The bearing does have a chamfer on one end so it fits nicely into to the star washer.  Now the armature almost wants to turn but doesn't, gets hot if i keep trying.  I can turn the armature with my finger, wheels move and there is no resistance so it should work. It mostly hums and every once in a while the armature jumps just a bit like it wants to turn.  Im at a loss, any ideas?  Could the armature itself be bad?  Thanks

Call Robert Barth. He runs the Train Rack in Perryopolis PA. He is very good. (724) 736-0488

One possible cause is a failed armature winding. Measure the resistance between all three commutator segments, it should be 1.7 to 2.0 ohms. Then measure resistance from each commutator segment to the center metal shaft, it should be close to infinite. You can also check the field coil. It should read 2.4 ohms.

At the commutator end there should be a fibre washer first, this is important as I remember because it stops any electrical shorting if the armature pushes upwards  towards the bearing/washer assembly.

If this is OK then I would disconnect the side rods and see if the motor can drive that single axle only, you may have something binding or not quartered correctly on the other axles.

Thanks, Ill check the ohms on the arm and the wheel quartering.  That could be it. Thanks

Disconnected drive rod from rear axle and still does not work.  I think there is a short somewhere but i cant determine where.  Armature Still just hums or jerks and gets hot.  Still can manually rotate armature with finger no problem.  

Thanks for all the info but I'm putting this away for a while or will sell it for parts.

The only way to prove it is mechanically fine will be to disconnect the motor/armature from the reverse unit and just wire it direct for one direction.

I wonder if someone in the past has messed with how it is wired up to the reverse unit. I have had a few which have also been finicky mechanically.

I got it!!   The eunit needed the old bath of contact cleaner spray!  I did it twice before i got action.  So there were 2 issues, the armature not fitted right and a sticky eunit.

the smoke unit works too!  

Take a bow. I'll bet that put a smile on A.C. Gilbert's face.

Its running great now!

Thanks to everyone who helped!  This forum has been a god send for me.

Boy i sure miss my drives to Homer City,  Jim.  Only wish i could have spent more money.

thanks also to amflyer and ukaflyer for the great help.

@pennsydave posted:

Thanks to everyone who helped!  This forum has been a god send for me.

Boy i sure miss my drives to Homer City,  Jim.  Only wish i could have spent more money.

thanks also to amflyer and ukaflyer for the great help.

That’s OK. A pool of knowledge exists out there with lots of different people and it is always good to share those experiences to help others.