When I receive a toy I determine needs rebuilding I first disassemble it completely. I am going to show you a 25c Citroen 2500KG Van I got off ebay. This is what it looked like when I got it.

I then take it apart completely as seen below. I drill out the rivet taking care not to damage the base plate. If you look carefully at the axles you will see that one end is considerably thinner than the other. I carefully grind the end off the axle to take the hubs off. Always grind the thin end of the axle off. I save the axle and will re-use it.

So what I end up with is a toy completely taken apart as seen below and ready to strip and paint. Now the fun really begins.

I will begin by stripping the toy and parts down to bare metal. I use the air powered glass bead machine for the body and parts and use a bench grinder wire wheel to clean the hubs and axles.

I then drill a small hole in the rivet stem to receive the new rivet I will make later on. Then the toy is ready for repainting.

Then I mix the paint up and paint the toy. I prefer to get the colour as close to original as I can, but that is a personal preference. I also paint the hubs and base plate as necessary. I cure each coat in my toaster oven for about 30 minutes on low heat. Usually I only need to apply one coat so the original details of the casting can be seen quite clearly.

Below is what I end up with once the painting is all done. Then it is just a matter of putting it together.

I begin by putting the hubs and axles back on the base. I use a 4 oz. ball peen hammer to round the axle ends over. It takes patience but works nicely. Avoid trying to speed it up or you can slip and damage the paint or worse, the castings.

Then I make the rivet to fasten the bottom back on. I use a galvanized siding nail with the rounded head. I chuck it in my drill press and use a file to carve it to the proper shape and size. Then I cut it off with some side cutters and glue it into the hole using 5 minute epoxy.

Once this is done it is set aside for the glue to dry. After that we are left with the finished product as seen below.

This is a relatively simple rebuild and took me a matter of about 4 hours from start to finish. Not having to wait for the paint to dry is a great advantage in this. If I have to make parts or fix castings I use a product called JB Kwik Weld, a 5 minute epoxy steel product. It machines and sands well and takes paint as nicely as the original casting. Click here to see a casting repaired with JB Kwik Weld.
I hope this has answered some questions about the hobby and has sparked an interest in starting your own workshop. It is really not that expensive to buy the tools I have and found work well. The glass beader was about $150.00, compressor $300.00, the Dremel tool I got for Christmas one year, and drill press about $50.00, the rest I picked up at garage sales and flea markets. Drop lots of hints about gift giving season and in no time your shop will be ready to go. Please let me know how your shop is coming and how you do your toys. I can always learn tips and tricks from others and am always open to chat about the hobby. If you are in the neighbourhood feel free to drop in for a tour and a coffee.
I have also been asked to redo some toys for other folks so follow here to see that work.