Triang Hornby X03 X04 Scalextric RX Brush Holder
This part repaired the brush holder on my X04 motor. It should also repair the brush holder on X03, and Scalextric RX motors from the 1970s.
I removed the old broken brush holder (which was held on with a pop rivet) and designed and installed this. Printed in PLA and I didn't find that it suffered from any heat related problems running for over 10 minutes flat out.
I would suggest printing multiple copies at a time to help with cooling, being a small part 0.1 resolution and 100% infill would be best.