602 Switcher driving me nuts and need some help

Growls forward, runs smooth backwards?

The problem is the lower bearing plate is floating in the stamped aluminum motor side frames as the factory staking has worked loose over the years.  The old Lionel fix for this was to "dent" the side frames with a punch, some shops used cardstock jammed in to firm up the plate.

I have had good luck using tiny black anodized self-tapping screws into drilled pilot holes to hold the bearing in place.

For a non-destructive fix, this beats them all.  Using the CRC QD or any non-residue contact cleaner, clean ALL oil & residue from between the sideframes & the bearing, using the nozzle to spray into the crevice.  Dry it out well, several hours or overnight.

Now use the regular "thin"(not gel) CA adhesive("Super Glue", Eastman 910, etc.) and flow the cement into the crevice on both sides, letting it creep in by capillary action to fill the gap.

In about 10 minutes, the loco is ready to be lubed(grease on gears, oil on pivots & bearings/axles) and will run like new. 

Anther thing I've run into is the side frames stakes get loose and the armature actually rubs the plates and runs lousy; on your 602 you make actually find the "sweet spot" of armature alignment by applying gentle pressure to the side frames as the motor runs.  As Rob suggests, clean the staking surface (4 total) and anchor them again. How?  I have used JB Quik under the stakings to hold the side frames in the proper alignment with the top field plate; there are also Lionel press tools that can re stake them.  Bottom line, as Rob mentioned, it is an armature alignment issue that causes problems with these be it the bottom black bearing plate or loose side frames.  Good lucke; Falcon70

Rob and Falcon, I will check for that.  I have had it apart a bunch of times and I think I would have noticed.  Let you know later today.  Thanks

To check for the lower bearing plate condition, run the engine upside down in a cradle and just squeeze the aluminum side frames together with your fingers while it's running. Try both directions.

I had the same problem...after trial and error with a wood toothpick it worked...

Update on my 602. When I put it on the track it will run now, but only in one direction with the motor in the rear.  It won't start in the normal way.  I have to put the voltage to the max to get it to move.  Then I can control it normally and will run very slow. Runs as low as 8 volts pulling a train of 7 or8 cars.  It won't even try to go the other direction.

I have checked motor frames and the little tiny ball bearing that the armature rides on, all good.  The brush end of the armature has a slot in it. I can put a tiny screw driver in it and turn the armature both ways freely and easily.  The locomotive moves in both directions very smoothly.  The worm and the brass gear it drives looks good and is tight to it's shaft.

I have cleaned the e-unit thoroughly, commutator is clean and brushes are clean.  I think the problem is electrical.

Thanks for the replies they helped.  I don't know what to do next.                                      

You describing the ailment of all of this family of locomotives, have you tried jamming some paper (index cards work good) as a temporary test ? ....as Rob and the others have mentioned, this really sounds like your issue...also, with the shell off, observe start up of the motor, does the armature try to jump up when starting to move? You can tell this by watching the brushes....they’ll look like they are trying to come out of their wells....turn the armature by hand till you see the stack laminates of the armature in the opening, is it all worn down shiny?.....Pat

Be sure the field winding is not touching the frame. Does it do anything like buzz when it should be running in forward? Possibly the e unit is wired incorrectly at the brushplate?

Rob is 100% right about the fix for my #602 switcher that was running fine in reverse but very poorly going forward.  I cut two 1/4 inch strips from a business card and wedged them between the lower bearing plate and the aluminum frame on the side away from the drive gears.  Now the engine runs smoothly in both directions -- an amazing improvement.  So far the card strips are staying in place without glue or screws.