Fixing broken Lego axle mounts

 Quite a few little Lego cars have been leaned or even stepped on in their time, which results in the fragile axle mounts breaking and the car then sitting with its bottom on the ground. But if the car can be easily opened, then here's how I fix that.

I use a window frame that's warped to uselessness, one of which will repair quite a few cars. It's the outer upright that's very useful, so the inner lip (part of the front of the frame) gets cut off.

First I cut a little notch in the middle, to the size of the axle diameter.

Next is a trial fit, to see if the axle turns freely and has a bit of vertical play. If the original mount on the other side is still present then match that, else you'll have to make two identical pieces, one for each side.

If the floor of the car has an incline then you'll need to cut the piece to allow for that. Next cut off the piece from the window frame.

You'll need to scrape the paint off the parts of the car's base where the piece touches, so it doesn't get in the way of the adhesive bond between the parts. Brush on some acetone, and position the red piece in place on the car's base. Use something to keep the base off your work surface.

Once the red piece is sitting where you want it, brush on some more acetone. This will run inbetween the two parts, melt them a little and help reinforce the bond between them. Repeat a few times, without touching the pieces (they can come loose with new acetone being applied). Any surplus will neatly evaporate (which means a ventilated workspace is recommended).

If the axle gets stuck as well, gently twist a wheel and it will come loose. This is why I use acetone instead of superglue, which will stick everything together in such a way that forcing loose the wheel will cause damage.

Final tip: if there's rust on the axles, then that can be cleaned off wth steel wool. If the axle is entirely loose then that's ideal for cleaning. If not, press some steel wool down on the axle and run the loose chassis back and forth on f ex a tablecloth to provide grip to the wheels.