Inherited a bunch of Lionel gear from mid-50s - looking for guidance on cleanup

Your on the right track lube wise.  Make sure the power cord on the ZW isnt all dry rotted and cracked, try wraping it around one of your fingers and see if the insulation on the power cord cracks or is nice and soft.  If it cracks or looks dry rotted, replace before you use it.  To remove the power pickup, its best to unsolder the wire at the collector/roller assembly, or where that wire terminates up at the E unit/reverse unit.  Do not use any steel wool ect as many models, such as the 681 have magne-traction and the magnets will attract fibers.  Mike

Thanks for the tip on the power pickup.  

I was planning to rewire the transformer cord - it does look like it's seen better days.  I did know about the magne-traction as well - scotch-brite pads will be the weapon of choice for cleaning up the tracks.

You are off to a good start using the K-line reprint of the Lionel service manual. It is an abridged version. One of the Lionel parts dealers, Olsen's, has put the entire factory service manual online, along with pages of their own creation. Here is a link: online service manual.

The only general advice I can give:

1 - Don't over lubricate. Excessive oil can foul brushes, and will attract dirt. 
2 - Not everything that moves should be lubricated.

I have run into locomotives where people put lubricant down the brush holders, and on the e-unit. All that does is foul the mechanisms. It's common for folks to apply lubricant to mechanisms such as the one found in a milk car. Over time the mechanisms get gummed up and have to be disassembled and cleaned to restore operation.

3 - when you do replace brushes, try to avoid replacing the springs unless they are damaged.

IMHO, you are better off cleaning and reusing the original springs. I find that the vast majority of the replacement springs that are available today apply too much pressure, which can cause the motor to run poorly.

  For the trucks, I was figuring I'd hit them with mineral spirits and a toothbrush to clean out the existing grease, then re-lubricate the gear train with red and tacky grease and oil as indicated at the points in the service manual (including the worm gear coming off the motor.  It seems like the wire going from the collector roller up into the body limits how much I can separate the trucks from the chassis - do people cut those wires and then use a crimp connector to put everything back together, or is it possible to remove the collector roller assembly from the rest of the truck while it gets stripped/relubricated? 

I unsolder the wire(s).
Some locomotives have an extra  wire running to an electromagnetic coupler, or a shoe to operate the electromagnetic coupler. Your 6250 should have this.

I would not get carried away with mineral spirits.
I recommend using a small flat object, such as a small flat screwdriver or knife to scoop out as much old grease as possible. I use the tip of a pointy knife (Xacto #11 blade works well) to clean any gunk out of the gear's teeth. Usually I stop there. Even hardened lubricant can usually be removed this way.

I hesitate to use mineral spirits out of concern that it would remove protective coatings, leaving bare metal to rust / corrode, and could wash lubricant out of hard to reach bearings.   (If anybody has tricks to get oil onto all four wheel bearing of a Lionel die cast diesel truck, I'd like to read about them).

Be careful where you use the lubricant with PTFE. Not good for wheel axles or anything handling common(ground) contact. It is a dielectric, which will hamper conductivity. #10w sewing machine oil is fine.

You had one heck of a grandpa, with a collection like that!

As far as cleaning the commutator, you only need to clean out the slots of dirt and carbon. The discoloring is called burnishing and should be left alone. You only need to resurface the commutator if there are deep grooves but this can be tricky as the copper is thin. Its best done on a lathe and then don't remove more than about .010".

Pete

A pencil eraser or a Walthers Bright Boy track polishing block used in HO scale is what I use to put a light polish on the commutator face.  Then I use either a tooth pick or the tip of my pocket knife to carefully clean out the slots.   Pledge furniture polish is what I use to put a slight shine to diecast and plastic engine/car bodies.  A soft paint brush is good for working it into the nooks and crannies.  Learned that trick from a hobby shop owner that was a Lionel Dealer starting right after WWII. I was his repair technician for the final decade he was open.  I really miss that set up we had, I got paid in store credit, which of coarse got spent on more Lionel.  I had one heck of a collection for someone in thier 20's!   Mike

I use a strip of green Scotch Brite pad for commutators. I find it works better and is less abrasive than wet/dry sandpaper. And Contact cleaner sprayed on the commutator and SB strip. When I get a "new" PW engine, I take the trucks off and at the least, soak them in alcohol. The F3s, I usually soak them in mineral spirits first, then alcohol (there's a lot more places on those horizontals and trucks to accumulate hardened lube). But be very careful when you remove the long worm gear that you put the spacer bushings on the ends in the same orientation. The hole in them is asymmetrical and it matters which way they orient.  I also prefer to rewire just about everything in there (including the "ribbon" wire connecting the motors).      Good luck with your new stuff......

Roger

It may be counter intuitive but a bright copper face on the comutator is NOT desirable. The mahogany color is correct.

Pete

I use 10-30w motor oil to clean the commuter, however make sure you COMPLETELY CLEAN the oil from the commuter face before running the motor.