Help with MPC era pullmor motors

Which loco?

i was just given the frame ..it would probably be a 200 series alco ...but mpc era

 

Those were cheaply made and ran nasty.

Marty thats what I figured... I didn't know if there was a "trick" that my peers have learned.  It is kind of a bizarre scene on my bench... I have two of these motor and frames to service.. and waiting in line are a pair of beautiful 773 Hudsons... one in black the other a 773e gunmetal grey..  I must say.. those Lionel Hudsons are a work of art!

Postwar versions of this motor suffer a loosening of the motor sides, which is part of the motor truck. If there is an old time Lionel service station near you, he can take care of it for you. This fix sometimes lasts a long time, sometimes they loosen up again. 

The 773 was a winner.

Did you change the brush springs too?

Some guys soldered the short end of the spring to the brush holder for better contact. If it has a set screw on top adjust the up/down of the armature so it has just minimal movement.

That is an early MPC motor and was troublesome. The later motor ran much better but suffered from off center wheel wobble.

I am not sure that it is getting poor contact, but it is worth a try at this point.  The brush plate has no set screw, it is molded solid with a hole on the underside so the armature sits inside.

 

I am siding with Marty....

 

It's probably a 8020.

 

The parallel plates/motor frames on these are vastly improved over the 200 series Alco / 600 series NW frames and motors of the post-1954 postwar era, are assembled much tighter and don't usually work loose at the stakings like the pre 1970 motors.

 

The problem you describe could be attributable to the oddball 1970-1971 only "scout type" hollow roller pickups. To truly assess the operation of the loco, you have to do it on the track with the rollers giving positive pressure on the wiper. For best performance, the rollers have to be cleaned well with an abrasive wheel on a Dremel, and the copper spring/wiper has to be cleaned with a good electrical contact cleaner. The plastic parts/halves only position the rollers and give a mounting/riveting point for the copper wiper, they are not part of the superstructure of the motor.

 

Even after all that cleaning, those rollers still do not work well. On the 8030 and 8031, leftover "Hillside" 2328-173 collector assemblies were added either at the factory or by dealers(as provided by MPC) to the non-powered trucks to improve performance.

 

For Alcos and switchers, the trucks are molded to accept the 1055-37 collector assemblies, but I've never seen these installed by MPC.

Rob... WOW   thanks for the great info..

 

The problem happens on the rails but also when I have the engine up and power clipped into the e unit.  So the rollers at this point are out of the picture

 

thanks again ... great info!

There is one other issue that could be the problem then.

 

Did you run it before doing the maintenance?

Rob

Yes it was one of th complaints when the customer dropped it off

Did you replace the nylon insulating washer under the one brushplate screw, and above the solder tab, so the solder tab is not shorted to ground?

Rob

The nylon washer is there .maybe I will isolate that tab to test .  Worth a.try

Bill, On occasion for these motor I have found too much slop on the brush housing.  When in reverse it would jam the armature as the motor reverse direction and thrusted in the opposite direction.

 

Loosen the top housing and adjust to center the armature.  Make sure smooth armature operation in both directions.  If too much vertical movement on the armature you can add a set screw.  Or add a nylon thrust washer on the shaft.  G

If this is the motor with no adjustable set screw on top, my experience is 9 times out of 10 adding a thrust washer, or two, will clear the problem. In reverse the armature shaft worm gear is 'climbing' the worm wheel an binding against the brush holder.

 

The other option is to swap out the brush holder with one that has the set screw.

 

George,  that was it... I added three washers and the issue stopped.. thanks as always... and thanks to all who passed on their knowledge

You are welcome.  G