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Pan Car Build: Part 1

This is part one in a series of articles that demonstrate how to properly build a pan car to get the most out of the chassis.

Aside from your usual tools, it's handy to have the following items (from left to right)-
• 3/8" fluted reamer
• Tapered (body) reamer
• 1/8" fluted reamer
• Pivot ball tool. IRS and CRC both make great tools for this.
• 800 grit sandpaper (not shown)
Here's the subject of our article. It's a Hyperdrive Pro 3 that's going to be used in the 17.5 truck class. It's in really good shape, but there's a few things that can be done make it even better.
First, we'll break the chassis down into the 4 major sections- rear pod, shocks, main chassis, and front end. For Part 1, we're going to focus on the rear pod.
Start by disassembling the rear pod and checking all of the parts on a flat surface to make sure that nothing is tweaked or bent. Make sure that you check both the aluminum plates as well as the upper and lower carbon pieces. A sheet of glass or a setup board works perfect for this.
Next, we're going to reassemble the pod on that same flat surface. start by screwing all of the plates/standoffs to the lower pod plate, but leave the scews slightly loose. Lay the pod upside down on your flat surface.
While pushing down on the lower pod plate to make sure that everything is flat and square, tighten the screws in a cross pattern. Once you've tightened the screws, make sure that the pod is still flat/square and doesn't rock on your flat surface.
Continue by flipping the pod over and attaching the upper pod plate using the same method that you used for the lower plate. If your pod has a rear cross brace, attach it last. Your rear pod should now be assembled nice and square.
Now it's time to look at the ride height adjusters. Most people overlook these and that's where you can lose a lot of efficiency. These are molded parts that are produced by the thousands, and I've never seen a pair that didn't need some kind of flashing cleaned up before using them.
Start by taking all of the excess flashing off from around the edges using your 800 grit sandpaper. Make sure that you only remove the flashing without taking too much material off of the actual adjuster.
Insert the adjusters into the pod plates and make sure that they're fully seated. The adjusters should snap right in without too much force. If you have a hard time getting them into the pod plates, try sanding them around the edges or even putting a slight bevel on the pod plate using an X-acto knife.
Once you have both adjusters mounted in the pod, use your 3/8" reamer to clean out the inner hole where the bearings sit. You want to spin it around by hand a few times on each side so that the bearings will easily press into place.
Here you can see the difference between an adjuster that's been sanded/reamed (left), and one that hasn't been touched yet (right). A few minutes spent on these will really free up your rear axle and eliminate binding in the axle bearings.
I use cheap $1 bearings from Avid for my rear axle, and I spray out all of the grease using motor spray. Just hit the bearing with a stream of spray until it free spins on it's own. You may have to work the bearing back and forth with your finger to free it up a little, but in the end it should free spin easily.
After spraying out the bearings, I put just a drop of really thin oil in each one. Avid makes some oil that works pretty well, as does Trinity's Royal Oil.
I'm not really going to go into detail on how to build a diff, since it's been done over and over. If you need to know, consult Google. There's tons of articles out there on how to properly build a pan car diff. That being said, I'll say that the two most important things (to me) to having a smooth diff are-

1. Keep it clean. Don't glob on a ton of diff lube, because it will only attract more dust and dirt. A little diff grease goes a long way.
2. Replace the outer hub bearing when the diff starts to feel gritty. That bearing takes a beating when you hit the outer wall of the track, so it's best to just replace it when you rebuild your diff. Bearings are cheap- replace it.
Now it's time to mount the t-bar to the pod (if your car uses a t-bar). Instead of just slapping everything together, we're going to give some attention to the pivot ball sockets. Notice the upper socket half in the upper left corner of the photo. Toss parts like this and replace them. A new set of sockets is around $3. Again, don't be a cheapskate.
If you look at the bottom sockets in the previous photo, you'll notice small raised circles on the mating surfaces. Take your 800 grit sandpaper on your flat surface and sand these away. We want that surface to be flat and smooth.
Here's a photo showing the difference that the sanding will make. The part on the left has been sanded, the part on the right is the original.
You can polish your pivot balls using a Dremel/drill and some aluminum polish (I like Mother's). If you have Teflon coated pivot balls, you should really only need to clean them. Polishing may remove the coating.
When assembling the pivot ball sockets onto the t-bar, just snug up the screws and check the ball for movement. The ball should be able to pivot around freely, but there shouldn't be any up/down slop in the joint. You may have to play with the socket screws a bit to get the feeling just right.
This next step is a bit of a no-brainer, but I've worked on a few chassis lately that didn't have t-bar spacers, so I figured that I'd cover it. Make sure that your t-bar isn't being bolted flat to the lower pod plate! There should be around 2mm worth of spacers lifting it up off of the power pod plate. If you don't space the t-bar up, then it can't flex like it's designed to do.
One last note about mounting the t-bar to the chassis. If your chassis has the ability to mount the rear pod with an offset, use it. Mount the t-bar as far to the left as the chassis will allow. In the photo to the left you can see that this chassis has the t-bar offset. The allen wrench is sitting on the centerline of the chassis.
This concludes the first part of our articles on how to properly build a pan car. We'll be covering the center/side shocks as well as the front end in the next installment.



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