Gilbert American Flyer Maintenance

Here’s a practical, preventative-maintenance routine for post-war (c. 1946–1966) Gilbert American Flyer S-gauge engines. It’s written for typical steamers and diesels with worm-drive motors, mechanical reversing units, and (on many steamers) smoke systems. Do the “Every Session” items before you run; do the rest by hours of operation.

*If you ever find a mistake on any of my pages, or you have a better way to do a certain procedure, PLEASE LET ME KNOW.

I am NOT the end all, be all in my knowledge of American Flyer trains!

WHAT YOU’LL NEED

  • Small flat/Phillips screwdrivers;
  • toothpicks;
  • cotton swabs;
  • soft brush;
  • 90–99% isopropyl alcohol;
  • plastic-safe contact cleaner (I prefer CRC 2-26 Cleaner, your mileage may vary);
  • plastic-safe light oil (Labelle 102/107 or sewing-machine oil);
  • plastic-safe grease (Labelle 106/TT gear grease);
  • paper towels;
  • nitrile gloves;
  • optional multimeter.

Every session (quick checks)

  1. Exterior and wheel treads – Dust the shell. Clean wheel treads with alcohol on a swab until they shine. Avoid the tires if your engine has rubber Pull-Mor bands (clean those with mild soap/water on a barely damp swab). Overly slick or oily treads = poor pickup.
  2. Pickup/wiper contacts – On AF two-rail locomotives, current is collected through the wheels and phosphor-bronze wipers. Gently clean the wheel backs and the wiper tips with alcohol; if oxidized, give a tiny shot of plastic-safe contact cleaner. Do not oil the contact surfaces.
  3. Reversing unit exercise – With the engine on a cradle or track, cycle power several times to be sure the mechanical reversing unit steps reliably (forward–neutral–reverse–neutral). Hesitation is your cue to do the annual service below.

Every 10–15 operating hours (light lube & running gear)

  1. Remove the shell – Photograph wiring before you lift the body. Set screws aside in labeled cups.
  2. Motor bearings (1 tiny drop each end) – Place one small drop of light oil on each end of the armature shaft where it enters the bearings. Keep all oil/grease off the commutator and brushes. Wipe excess.
  3. Axle journals – Spin each axle while applying a pin-point drop of oil where the axle passes through the frame/truck.
  4. Gears – If grease looks dry or caked, wipe off the old residue and apply a thin film of plastic-safe grease to the worm and worm gear. Do not pack it.
  5. Side rods & valve gear (steam) – With a toothpick, place the tiniest dot of oil on side-rod pins and crossheads; wipe any fling-off. (Oil on tires will kill traction.)

Every 25–40 hours (electrical service & traction)

  1. Commutator & brushes
    • Remove brush caps (or springs) carefully; catch the brushes.
    • Clean the commutator’s copper segments with alcohol on a swab until no brown/black transfers.
    • Use a toothpick to lift residue from the segment gaps; never use a metal pick.
    • Replace oil-soaked, chipped, or very short brushes and weak springs. Reinstall dry and clean. (Oil here causes arcing.)
  2. Reversing unit (mechanical “sequencer”)
  • Blow out dust; clean the drum/fingers and the plunger path with contact cleaner on a swab.
  • Do not oil the drum, fingers, or the solenoid bore; they should be clean and dry so the pawl/plunger moves crisply.
  • Verify finger pressure and clean contacts until switching is consistent at moderate voltage.
  1. Pull-Mor traction tires (if equipped; many AF engines from 1953 onward)
  • Inspect for cracks, flat spots, or looseness.
  • Early “molded-on” Pull-Mor wheels require wheel replacement; later 5-digit models often use removable rubber bands you can replace yourself.

Beginning of the season (annual deep service)

  1. Wiring & insulation – Inspect cloth/rubber leads for brittleness, melted spots, or frays. Replace or heat-shrink as needed. Check all solder joints and ground paths from trucks to frame.
  2. Full gear train cleaning – Degrease old, hardened grease from the worm, idlers, and driver gear with alcohol; dry thoroughly; re-grease lightly. Trains
  3. Couplers – Ensure knuckles pivot freely; clean pivot and latch faces; a micro-drop of oil on the knuckle pin only (keep oil off trip faces).
  4. Smoke unit (steam) – Identify which type you have and service accordingly:
  • Conventional “puffer” in the locomotive: confirm the wick is clean and not charred; replace if hard or black. Add 3–5 drops of approved smoke fluid to the wick—never run dry.
  • Smoke-In-Tender (SIT) with bellows (on specific models): inspect the bellows for cracks and replace fabric if stiff or torn; keep liquid out of the bellows chamber. Many owners convert worn bellows to the later piston-cylinder kit for reliability.

Reassembly & test

  1. Reassemble carefully – Route wires exactly as before so nothing rubs the flywheel, worm, or side rods.
  2. Bench test – On a cradle or rollers, apply 5–7 VAC and watch for smooth start-up. Listen for grinding (too little grease) or squeal (dry bearings). Verify reliable reverse-unit cycling and, for steamers, steady smoke puffs at medium throttle.
  3. Track test – Run light for a few minutes, then with a short train. Re-check that wheels and tires stayed dry and clean.

Do / Don’t cheat sheet

  • Do: use tiny amounts of plastic-safe oil/grease; keep commutator/brushes bone-dry and clean; keep contacts oxidation-free.
  • Don’t: spray general lubricants (WD-40 etc.) into motors/reverse units; oil the wipers or the reverse-unit drum; soak traction tires or bellows in solvents.

Suggested intervals

  • Every session: wheels/wipers clean, quick reverse-unit check.
  • 10–15 hrs: bearings, journals, gear touch-up, rods.
  • 25–40 hrs: commutator/brush service; reverse-unit cleaning; Pull-Mor inspection.
  • Annually / start of season: full gear clean/re-grease; wiring check; smoke-unit service.

Notes specific to American Flyer

  • Many AF steamers and diesels used worm drives with phosphor-bronze wipers and a mechanical reverse unit. Keeping the reverse unit clean and dry is crucial for reliable stepping.
  • “Pull-Mor” traction (introduced in 1953) improved pulling power; know whether your loco has molded-on tires (wheel swap) or removable bands (simple replacement).
  • If your locomotive has Smoke-In-Tender, the bellows are a wear item; replace fabric or consider the cylinder conversion for a durable fix.

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