build A Dune Buggy - rear Axle Suspension - Photo 11163120

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<strong>Rear Axle Prep: </strong>The rear Dynatrac Pro-Rock 60 is pretty abuse-proof, but since we needed a place to mount our rear-steer ram and our suspension links, it seemed obvious that a few trusses would work as both mounts and strengthening components.

<strong>Fuel Tank: </strong>Let's start with the buggy's juicebox-its fuel tank. Buying an aftermarket fuel cell would have been quick and easy, but then we would have been building the buggy around it. Instead we built our own to fit perfectly in the back of the buggy with no wasted space.

<strong>Fuel Tank: </strong>Most of the aluminum on this buggy is 1/8-inch 5052 that I got in 5x12-foot sheets from Industrial Metal Supply. We'll use roughly three sheets for the floorboard, firewall, body panels, and fuel tank. The fuel tank incorporates internal baffles to hinder sloshing fuel and a sump to keep fuel near the pick-up during inclines and low fuel levels.

<strong>Fuel Tank: </strong>Inside the tank we used an Edelbrock fuel pump. Keeping the pump submerged in fuel helps cool it and improves longevity. It also makes it quieter. The pump and return lines are stainless tubing and there is a rollover check valve at the top plate also to ensure all the go-juice stays inside should Fun Buggy go belly-up.

<strong>Fuel Tank: </strong>Burroughs pressure-tested the tank after finish-welding it and found it secure and ready to fill up. The tank wedges in behind the passenger compartment and uses a fender fuel-filler kit and sending unit from JAZ Products. Notice how the tank is wedged for the coolant plumbing going back to the radiator.

<strong>Air Bumps: </strong>The nitrogen-charged Fox 4-inch airbumps act as progressively stiffer bumpstops for the final 4 inches of suspension uptravel and were installed on all four corners of the Fun Buggy. This helps reduce abuse from the shocks when landing a big jump or coming down hard off an obstacle.

<strong>Air Bumps: </strong>To mount the airbumps we took a set of the Poly Performance airbump cans and built some dimple-died sheetmetal mounting brackets, using a piece of tubing to represent the bumpstop during welding. We first made a template of the brackets from posterboard, copied it in 0.090-thick steel plate, and mounted them as close to the shocks as possible so as to compress at the same rate as the shocks. On the axle there is a 1/4-inch-thick plate that the airbumps hit at full compression.

<strong>Rear Axle Prep: </strong>The rear Dynatrac Pro-Rock 60 is pretty abuse-proof, but since we needed a place to mount our rear-steer ram and our suspension links, it seemed obvious that a few trusses would work as both mounts and strengthening components.

<strong>Rear Axle Prep: </strong>The first step was a rear ram mount that also acts as a rearward truss. This was a prototype, but like many parts on this buggy, it is scheduled for production from Poly Performance as both a front and rear truss that doubles as a ram mount. The center of the truss is removable to access the differential, while the outer ends of the truss protect the smooth shafts of the mil-spec green PSC double-ended ram.

<strong>Rear Axle Prep: </strong>The upper four-link mounts bolted onto the Dynatrac axle, but we replaced them with this 3/16-inch-thick over-the-axle truss that will defend against bending while the buggy is having fun on the trail. This Poly Performance truss is available for most differentials, including the Dana 35, 44, and 60, the Ford 8.8- and 9-inch, and the Chevy Corporate 14-bolt.

<strong>Rear Axle Prep: </strong>One addition to the rear truss was this small pulley. It acts as the snatch block for a Warn 1,500-pound ATV winch. This mini winch is used to compress the suspension during extremely steep descents when a low center of gravity is a benefit.

<strong>Rear Axle Prep: </strong>That rear mini winch is mounted just between the rear-mounted radiator and the storage tub. A larger winch could have doubled as a rear recovery winch, and to do it again we would have gone that route, but with the limited space this mini winch will be fine.

<strong>Engine Cage: </strong>If the buggy ever ends up on its lid, I'm going to be bummed, but we designed an engine rollcage to protect the engine should any rocks be protruding where we land. Before we installed the cage, we needed a way to remove the cage should we need to pull out the engine. We used these Poly Performance tube clamps that weld in the tubes of the engine cage and are bolted together with two bolts.

<strong>Fluids: </strong>After the engine cage was complete, we added two PSC power-steering reservoirs for the dual steering pumps. Since we are running front and rear steer, we have separate pumps so that we can always steer either end without the rams waiting for fluid from one pump. And we can get off the trail even if one of the pumps should fail.

<strong>Fluids: </strong>To keep the steering fluid cool, I'm running a front B&M cooler. Only the front steering box and ram assist will have a cooler since it will be used the most while the rear steering system has much more fluid capacity, since its lines run so far back in the vehicle. An additional cooler is for the transmission. It has a temperature sensor and a small fan attached and will pull air in through both coolers simultaneously. That's all for this month, folks, but check out our Web site (www.4wheeloffroad.com) for weekly buggy updates, previous buggy buildup stories, and tons more photos.

<strong>Sway Bar: </strong>The four-link suspension is designed for optimum off-road use, but to add some stability to the system, we used a Currie Anti-rock sway bar. The Anti-rock allows the axle to articulate while controlling the suspension so that more equal tire pressure is applied to all corners of the vehicle. The multiple link positions will allow us to fine-tune it for the best performance. We used a Universal 353/4 -inch bar with steel arms so we could bend the arms to clear all the springs and airbumps. (Check out the sway bar mounted in the Rear Axle Prep sidebar.)