Maintenance: Tonka Clutch Popper

The great thing about these old Tonka’s is that in many ways they were built to be repaired. The simple and solid design not only allowed them to be used and abused (sometimes brutally), but also to be repaired/maintained to keep them coming back for more punishment:). This has always been true for the original Tonka steel trucks and cars, and is also much the same for these Clutch Poppers.

A photograph of a disassembled Tonka Clutch Popper
Tonka Clutch Popper – Chevy Monza – Disassembled

It doesn’t really take a lot to bring one of these things back to life and almost all are repairable (caveat – some may be permanently stuffed if they’ve been run over, dropped from a 10 story building, sat at the bottom of the ocean). All you’ll need to do the majority of the things listed below are:

  • A star Allen key or screwdriver (number 10 size)
  • A Phillips head screwdriver (some models)
  • Tweezers
  • A very fine screwdriver or similar (for scraping out crud)
  • Lube (I recommend CRC range – 556)
  • Sandpaper
  • Car polish/wax
  • Plastic cleaner (like Armour All or similar, optional)
  • Cotton buds
  • Cloth
  • A vice can come in handy
  • A drill (only if you need to remove the motor – not usually required)

The main general maintenance points relate to :

  1. Disassembly
  2. Cleaning up the wheel axles and motor (outside)
  3. Lube and clean the motor
  4. Rear tire sanding (for re-grip)
  5. Fixing spin-out (hook/slice)/ Adding weight + part 2 (fixing flywheel movement)
  6. Fix ‘slipping’ wheels (where they are no longer gripping the axle)
  7. Remove the ‘Turbo sound’ (if anyone finds it annoying)
  8. Clean up the main body (steel part)
  9. Clean up the plastic parts (windows and base)

If you complete all these Tonka maintenance things (if needed, but typically always the first three & the cleaning), then you’ll have it back running like new (well close enough:))

I’ll write a blog post about each of these things, whatever else crops and other similar stuff, including some photos and maybe videos, and they will appear below.

A bit about the motor

tonka clutch popper motor photograph

So I will do a blog post about this, and a video at some point, but there are a couple of key things to know about this motor before you get started cleaning/fixing one up.

First point is that these Clutch Popper motors are quite highly geared (meaning a low gear ratio) for such a little friction motor. They have a fair few reduction gears that translate a single rotation of the wheels into maybe 50+ rotations of the flywheel (you’d need a super slow-mo cam to accurately measure it, or calculate from the gear sizes themselves). When spun up to full speed then engaged with the rear axle, another gear translation gets those rear wheels moving very quick (if everything is in good working order). This means if run at full speed it can be sensitive to smooth surfaces, unless you add additional weight and/or put down some kind of more grippy runway for it to run on. Why the engineers who designed this motor decided they needed to push the envelope to this extent for a toy friction motor is lost in the mists of time:). But if you’re really keen on this stuff, through a bit of sleuthing I’ve found that it is the combination of these two patents:
Running toy with a flywheel (Yutaka, Ohashi: filed 1977, approved 1978) & Gear changing mechanism for toy vehicle driving devices (Masubuchi, Hiroshi: filed 1978, approved 1983). Happy reading! Clicking on “Images” in the top of those links will give you the full patent document.

Practically, this motor is made up of brass and nylon gears, and maybe some nickel in there around the axle I’m not sure. The use of some nylon gears in here is by design due to their ability to deform (in a good way) under stress, lightness (one of these gears in the one that drops out of the way when the clutch is engaged), and not least their ability to run dry due to a certain amount of friction reduction (slippi-ness) being a part of the material itself. And they are actually very hard wearing and used even in industrial applications believe it or not. When these motors came out of the factory, apart from some light grease around the gear rod joints, axles and bushings, they were dry. Which for this motor (combo of brass and nylon) is a good thing, any dust that does get in there has nothing really stick to. Brass and nylon also have natural low friction properties, it’s one of the reasons why they are used in gearing’s in the first place . The challenge is what to do after decades of dust and crap have slowly invaded the motor (the dust cover can only keep out so much but does do a good job) and built up in there. If you can somehow get it back to its original dry state, with some minimal lube around the joints & bushings then that would be good way to go (maybe some dry lube inside if needed). There are a number of things that make that difficult but I’ll leave that for a future post. Rule of thumb should be – if you get it running pretty well with just some lube (CRC-556 or synthetic type – penetrative loosening up but safe/non-destructive on all materials) outside of the motor then leave it at that. The risk you run with putting any actual lube (not 556) inside the motor is that you create a grinding paste that will carve into those nylon gears and ultimately shear one of the teeth off. Anyway some food for thought!

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