This article originally appeared on the Racing to the Future™ website in 2013 and was included as part of the tuning projects for 3rd to 12th grade students participating in the program. These steps could also be used for the Viper and BSRT chassis.
Upon request I have put together a basic “How-To” article showing the disassembly, cleaning and re-assembly of the Tomy AFX Super G-Plus chassis. We will also cover where to lubricate the chassis to increase the performance.
Here are pictures of the bottom and top of the Tomy AFX Super G-Plus Chassis (SG+). From this point forward we will show how to take it apart and what steps need extra care and what to watch for.
Step 1:
If the chassis you have chosen has a full width body, like a stock car or street car, it will have the body mount clip. Remove the clip by gently prying it to the side and lifting up and off of the main chassis.
Step 2:
Next, remove the front and rear wheels and axles. The rear axle assembly simply snaps out. The front axle assembly requires you to remove one of the wheels and slide the front axle out of the chassis. Do this by gently turning the front wheels in opposite directions while pulling them away from the axle. One wheel should start to turn and come off the axle. Take caution not to bend the axle while removing the front wheels.
Steps 3 & 4:
Right: Remove the pick up shoes and the pick up shoe springs. If the pick up shoe spring feels stuck, use tweezers and gently turn them counter-clockwise until they lift free of the spring cup they sit in. Left: Next, remove the guide pin. Take caution not to bend the pin as you remove it.
You may notice the chassis is cracked on the sample. It was broken prior to this article and not from any of the steps taken here. It was repaired during the re-assembly process.
Step 5:
Remove the traction magnet retainer clip by prying it from the chassis on one side and pulling it over the top of the chassis to remove it. CAUTION! This is a fragile part and can be easily broken. Take your time in removing this piece. If it breaks you will need to get a replacement or glue your traction magnets in place. Gluing may not be allowed by certain clubs/organization rules, so check first before doing so.
Step 6:
The next step is to remove the two traction magnets. They simply slide out of the cavity that holds them in place on the chassis.
Step 7:
Pry the main chassis open slightly and push the motor and magnet assembly from the bottom of the chassis, up and out of the main chassis component. It should come out like the one pictured above. DO NOT let the armature come out of the front bulkhead/motor brush assembly yet. Doing so now will damage the motor brushes and springs.
Step 8:
Remove the motor magnets, they should be stuck to the armature. Be sure not to pull the armature free of the front bulkhead./motor brush assembly.
Step 9:
Here you can see we still have the armature in place (the shaft is visible in the center). The arrows show where the motor brush springs are located. These springs keep the motor brushes pressed to the armature’s commutator. We need to separate the brushes before we can remove the armature.
Here’s an inside the bulkhead view after we remove the armature, to give you an idea of what you are working with. The motor brushes are in the center of the assembly and the springs hold them in place against the armature’s comm. In this picture they are touching. We need to separate these before removing or installing an armature.
Step 10:
Now we will make a tool for spreading the motor brush springs to safely remove the armature. A Tomy AFX Motor Tool can be purchased from your hobby store, webstore or local race facility. Or you can fabricate one using a paperclip. Use the smaller end of the paper clip and cut the excess away using wire cutters. Leave about 1/2 inch to 3/4” of wire on each leg. Separate the ends a bit so they will hold tension against the motor brush springs and keep them open while you remove the armature. You should have something that looks like the picture below on the right.
Step 11:
So it’s easier to see, the next steps will not have the armature in place. In the picture above, you can see the motor brush springs and where they are located.
Step 12:
Insert the paperclip tool you made into the motor brush bulkhead as shown.
Step 13:
Here’s a shot from the inside. Notice where the paperclip tool is positioned.
Step 14:
Turn the tool clockwise until the brushes separate as shown. This creates enough space for the armature to be safely pulled from the bulkhead. This same procedure must be followed when reassembling the chassis. By separating the brushes, the armature will not break the brushes off during disassembly or reassembly.
Step 15:
So here it is from the outside view. The paperclip tool is in place and turned. You may have to hold it in place to keep the brushes separated as you remove the armature.
Step 16:
You should now have three pieces, the motor brush assembly, the front bulkhead clip and the armature assembly. For the tune up steps we are doing, you do not have to remove the pinion gear or brass bushing from the armature. Just make sure to remove any lint or debris that may have gathered there. If the pinion gear is worn, replace it with a stock or performance replacement gear.
Step 17:
Take a close look at the commutator (the copper colored barrel at the front) of your armature. Most will have some dirt and build up from use. This can be cleaned using a soft eraser or very fine sandpaper, 1200 grit or higher.
Step 18:
Be very gentle when cleaning the comm. It can be damaged very easily. Use only a little pressure when cleaning. First, very gently wipe the excess oil and dirt from the comm. You can see how much was wiped away in the picture on the right. But it’s still not clean enough to get maximum performance. Dirt and oil do not conduct electricity and hamper performance.
Step 19:
Be very gentle when cleaning the comm. It can be damaged very easily. Use only a little pressure when cleaning. I can’t say that enough! Now we will use a soft eraser to remove the remaining gunk from the comm. Once you have cleaned the comm with the eraser, wipe it off with a dry cloth to remove any residue the eraser may leave behind.
Step 20:
Time to reassemble. Top Left: Place the front bulkhead clip in place on the armature. Top Right: Next, using the paperclip tool, separate the brushes in the motor brush assembly and slide it back over the comm on the armature making sure the brushes are apart (Bottom Left and Right). Take your time on reassembling this stage. If you break the motor brushes, you will have to replace the whole assembly.
Step 21:
Once you have everything in place you can turn the paperclip tool and release the brushes onto the comm and then remove the paper clip tool.
Step 22:
Place your motor magnets back in position. Note the dial on the motor brush housing…it faces the bottom of the chassis. So does the painted side of the magnets. This helps identify which side the crown gear will go on, facing the pinion gear.
Stepp 23:
Here are the front electrical contacts. The area facing the camera makes contact with the motor brush assembly. Clean these with an Emory board or fine file as used here. This improves the electrical connectivity between the parts.
Step 24:
Place the motor assembly on the top of the chassis. Gently pull the sides of the chassis apart and push the motor assembly into the chassis. Make sure all tabs are snapped into place and that nothing binds or is bowed out of shape.
Step 25:
Your chassis should now look like this. Replace the traction magnets and their retaining clip. Remember the clip is fragile so be gentle prying in back into position. Next, clean you pick up shoes and reinstall the springs and shoes. Lastly replace the body mount clip.
Step 26:
With the clips still off, we will point out the places from the top of the chassis to add a fine light oil for lubrication of moving parts. The bottom view shows additional lubrication points.
That wraps up the tuning procedures for the Tomy AFX Super G-Plus. Now it’s time to go out on the track and turn some laps.