8111 DT&I motor binds up

I'm not an expert in Pullmor motors, but I had a very similar issue with one of mine. There's a little set screw (like 0.050" hex or so) in the brushplate on the end of the armature that you can use to tune the distance that the armature can "climb" when it changes direction. I would suggest turning that set screw down a little bit so that the armature doesn't climb out of position. I also replaced the motor brushes in my Pullmor and lubricated thoroughly (including a drop of oil on the backside of that set screw) which greatly improved performance.

Looks like your missing the "thrust bearing screw #8030-118" that goes on top end of armature in brush plate. Then you can adjust armature play. Screw may be there but its screwed in to far and can't see it. Also check lower armature bearing hole for debris and relube.

^^Ken and ^^Frank nailed it.  The only thing I would add, is to make sure all old hardened grease is removed from the "sump."  Then relubricate with a fresh teflon grease.  As long as the worm wheel in the truck isn't chewed up you should be able to restore smooth operation in both directions.

Your brushplate is black so it's difficult to see in your photos.  The "bump" that sticks up exactly halfway between the brush wells is meant to hold a tiny, fine-threaded Allen screw (part number referenced above.)  And the purpose of that screw is to limit vertical thrust play of the armature.

Your armature does seem to have some extra movement.  I had a MPC 8361 Alco with the same drivetrain as your DT&I that I got when I was 6 years old.  It had a million miles on it and the spur gears in the truck were worn to the point of almost falling off their studs.  It still ran smoothly in both directions, so I don't think that's the problem.  Could you swap in another armature and brushplate to test?  Worst case, you should be able to find another MPC power truck with AAR type A side frames for small money on eBay.

I am so sorry! I posted a different brushplate! Mine is a closed cap. Here’s the correct picture snd I’ll delete the incorrect post. I don’t see where a screw would go.

Hm.  I'm sure you could get the later brushplate from any major Lionel parts vendor.  The ones I've seen are usually white nylon.  You could also remove the one you have and drill it out from the inside to take the screw.  Others on here could probably tell you what size the body drill would have to be, to achieve a snug "factory" fit.

Before doing any of that, I would temporarily swap in another armature and brushplate to rule out any issues with the gears in the truck.  My $.02.

Some used a tiny ball bearing in the plate. I've used a ball from one of those ball key chains.

Try running it with this screw removed.

I’m giving that a try. I did a quick test and the motor did seem different but i had no time to really check it out.  (Busy moving my mother in law).  
   What’s the reasoning behind it working by removing wires?

@Mike23 posted:

What’s the reasoning behind it working by removing wires?

Not removing wire(s) here, but freeing the strain relief / anchor point(the solder tab) from a potential short to chassis ground. This is not an electrical connection and should be completely isolated from the metal screw... the nylon washer(202-108) appears to be in place but perhaps compromised.

Any progress?

thanks for asking.

I bought a brushplate with the screw in the top and adjusted it a few times with NO luck. So far I've added a ball bearing type "filler"  in the old brushplate hole to take up space..Removed the two wires attached to the nylon screw side.. reattached them..new brushes..Tried a different motor (from a similar switcher...made sure the coil wires were not touching other wires. and anything else suggested for this simple motor.

I've put it aside for now. I have touched every part except the wiring which seems fine. I'll post a video.

The e unit on an engine that I repaired had resistance on one leg that prohibited the field magnet to operate. Fix was a new e unit.

@Gerald Jackson posted:

The e unit on an engine that I repaired had resistance on one leg that prohibited the field magnet to operate. Fix was a new e unit.

With a 2 position e unit?

Pat

correct

Well, first off, this engine doesn’t have an e-unit at all, just a lever that switches the double wound field. This motor is about as simple as simple gets. If there’s no mechanical bind, preventing the magic from happening, & the wiring is correct without anything touching one another, then the 2 most likely suspects are either an open segment on the armature, or the 2 fields are being energized at the same time due to a short in the field winding(s) …….The OP can verify the armature segments have continuity between the three poles, and no continuity to the shaft ( that indicates a shorted armature winding ) if that’s ok, and still no joy with no reason, but the motor spins smoothly by finger tips, then the top suspect would be both fields are being energized at the same time. The OP can test that theory by isolating one or the other windings in the field. Either the red or the green. The motor should then run in one direction only.

Pat

@Gerald Jackson posted:

The e unit on an engine that I repaired had resistance on one leg that prohibited the field magnet to operate. Fix was a new e unit.

@harmonyards posted:

With a 2 position e unit?

Pat

@Gerald Jackson posted:

correct

That doesn't really make sense... the 2 position has just a rudimentary SPDT switch to select either of the two fields... no "legs" to it...

@ADCX Rob posted:

That doesn't really make sense... the 2 position has just a rudimentary SPDT switch to select either of the two fields... no "legs" to it...

That’s what I was eluding to,…….it makes no sense …

Pat

Terminology. When I stated 'leg' , that was one side of the switch.