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I have Plate, Modified 2 x 2 with Wheels Red with metal axles that have developed rust and I need to sanitise them, as I have rust even on the plastic pieces

This is an example of wheels I need to disassemble:

122c01 Plate Special 2 x 2 with Wheels Red (from rebrickable.com)

Before trying more things and avoid breaking them, I would like to know if is it possible to extract the axles with no damage (the axles are inserted by pressure) or are they glued and should try to clean the rust without disassembly

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  • 1
    Not an answer, just a comment, as I can't prove a negative: Bricklink treats the entire assembly as one part, indicating that it is not meant to be disassembled. That of course doesn't mean it can't be disassembled though, but could mean that such disassembly would cause damage to the parts.
    – zovits
    Sep 13 at 11:44
  • @zovits thanks for your comment, maybe you are right. I assume they are one part because they are meant to be together, not because it cannot be disassembled, or because of the metal axle not being a LEGO part. Maybe I cannot disassemble because of the rust or the material expansion, or they are just glued! That's because I am asking :D I will try something by the weekend if I do not get an answer :(
    – Jade
    Sep 13 at 19:11
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From accidentally destroying some older wheels (decades on a sunny windowsill can make red parts brittle), I think you're out of luck.

The ends of the metal axles I've seen have had splines formed into them, then as far as I can see the plastic is moulded over the top. To see what I mean, imagine something like 32209 Technic Axle 5.5L with Stop, then covering the end with the stop with modelling clay - you won't get the clay off in one piece.

The good news is that ABS (the plastic used in most Lego parts) has good resistance to oxalic acid and you can get rust removers based on oxalic acid (some advice here). It might turn the steel black; I know phosphoric acid does. Note that phosphoric acid, citric acid, and acetic acid* aren't good for ABS, ruling out many commercial rust-removers and home-made recipes. There's always a chance of damage, but less so than trying to get the assembly apart.

I tried an experiment. After about an hour and a half in vinegar, the plastic was unaffected, but the rust hadn't reduced, so you may need something stronger.

But before I put the assembly into the vinegar I noticed one of the wheels was cracked (actually both now I look at the photo!), so I risked prising it off. After scrubbing some rust off using steel wool you can see the groove in the axle where the plastic is moulded to grip it (red arrow), confirming that it's not coming off without damage. I was slightly wrong though - this part isn't splined, presumably because it doesn't matter if the wheel slips round the axle. Axle with groove

If you insist on disassembly, applying enough heat to just the axle will soften the plastic touching it, allowing you to pull it out. Reassembly would need glue. But I think (from memory, bricklink doesn't have a picture of the underside) you couldn't heat the axle without melting the plate.


* From the source I used, 20% acetic acid is bad, but vinegar (4-8% acetic acid) is good. Whether the soaking time to remove the rust is long enough to cause problems for the plastic would require an experiment.

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  • What about vinegar? It is much more common than oxalic acid and is also known to be used for rust removal. It also seem to have "A-excellent" rating on the list you've attached.
    – Alex
    Sep 14 at 12:15
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    @Alex I searched "acetic acid" in that list (vinegar being 4-8% acetic acid) and even at 20% it gets C - "should not be used". I didn't search vinegar by name. It might be worth trying it. If the wheels are important, testing on a damaged/less useful part (perhaps of the same colour) might be a good idea.
    – Chris H
    Sep 14 at 12:23
  • I was considering the heat solution in case it was using some kind of pressure system, you just confirmed some of my worries. I got the wheels on a similar 2nd hand package you speak about and they are the only pieces of that kind I have so I did not want to risk breaking them. I will try my best to clean them without disassembling and not ruining them!
    – Jade
    Sep 15 at 12:13

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