The Build – Part 2
The next step of our Speed Passion LM-1 LeMans build is the assembly of the rear axle. We’ll also be assembling the differential as well.
While not the norm, we do have to build the ENTIRE rear axle, which means pinning the inner diff hub to the chassis. This might be a bit difficult to do, but if you have a good set of pliers and some patience, it should be a piece of cake.
We’ll be working with diff grease, so have some clean rags or towels handy just in case of any spills.
With the Speed Passion motor installed, it is extremely difficult to solder the wires onto it. Since I wanted to replace the wires on the ESC with a smaller gauge anyway (to help keep the rear pod’s movement free), I went ahead and measured out the length and and soldered them to the motor prior to installation.
Step 1 is a bit of a freak step, seeing as most Pan Car manufacturers already do this step for you. We have to pin the inner hub to the axle. While it might seem, at first, to be a bit of a chore, it’s not all that bad. The first step is to pre-press the pin into the hole. This is probably the hardest step, but easier to do with the hub off the axle. Push it in just far enough to hold it in place.
Slide the axle into place and line up the holes in both the axle and hub. Once set, carefully press the pin all the way through the assembly. Note the direction of the hub to the axle.
Using the 0-offset axle ride height spacers, press a bearing into each, then press them into the rear pod as shown.
Slide a single, plastic shim onto the axle. Slide that assembly through the axle ride height spacers.
On the other side of the pod, slide another plastic shim onto the axle followed by the aluminum spacer and wheel adapter. Use the 3x3mm set screw to hold the wheel adapter in place. Do not press the wheel adapter to firmly onto the axle; you want a minute bit of side-to-side play.
Spin the axle assembly to make sure it rotates freely. It might not spin super long (since there is no weight on the axle), but it should be free.
Apply a small dab of diff grease to the inner hub and set the diff ring into place.
Slide the spur gear into place and fill the outer holes with diff grease. Press the 18 1/8″ diff balls into the outer holes as shown. Set the car to the side. The current diff assembly should stay in tact.
Apply a small dab of diff grease to the outer hub and set the diff ring into place. Press a 12x8mm bearing into the hub as shown.
Now we need to assemble the outer thrust washer. The picture shows the order of the parts; 11x5mm bearing, 2 5mm spring washers, 5x11mm washer and 4mm flanged nut.
Here is how I get them all installed in an easy manner. Slide the parts on a wrench, tilt the car on its side and place the tip of the wrench onto the tip of the axle (within the hub). Wahlah…parts just slide right into place. Two quick notes; 1) make sure the bearing drops ALL the way down into the hub and 2) the 5mm spring washers should be facing each other (cone side out).
Fasten down the 4mm flanged nut, ‘working’ the diff every couple turns. To test how tight it is, slide the rear tires onto the axle and, while holding each tire tightly, try and spin the diff gear with your thumb. If you can spin it, the diff is too loose. Tighten it up. If you can’t (or it’s extremely hard to), you’re in about the right place to start off. You can do final adjustments on the track.
Remove the tires and slide the axle end cap into place, lining up the the through-holes in both the cap and hub. Slide the 2x13mm pin into place and secure with the set screw. Do not overtighten.
As I mentioned earlier, the wires are very difficult to install once the motor is in the car. I wanted 16G wire to keep the rear pod from binding so measured out the length and installed them now. I also installed the sensor wire as well.
The instructions show you using a pair of standard 3x8mm screws to hold the motor in place. That’s well and good, but I like to also use washers. I added a pair to the screws for this step.
The motor just drops right in and is an easy install. We’ll hook the wires up to the ESC in a later step.
Part 3 – Assembling the steering.