The Dumpster is my '65 Dodge M37 project truck named after its ugly looks and treasure trove of goodies hidden inside. Showing how to swap in a complete drivetrain and build a suspension no matter what vehicle you start with is the goal of this truck. I'm sure many of you won't be building M37s, but many of the steps apply to your own custom wheeler. In the end I should have a great riding on- and off-road machine that can drive cross-country or across the countryside while keeping the ugly old truck patina it earned over the past 45 years. 1. When designing a suspension it is important to determine the ride height as well as full-stuff and droop positions. I am using 11-inch-travel Ford Super Duty coilover shocks from Icon Vehicle Dynamics, and I want the axle to have 51/4 inches of uptravel and 53/4 inches of downtravel. This nearly equal amounts of travel should make the suspension work well all around.1. When designing a suspension it is important to determine the ride height as well In our March issue I started the front link suspension and followed up on the GMC 6.0L truck V-8 engine we're installing at Pacific Fabrication in Morgan Hill, California (see this story online in the Project Trucks section of 4wheeloffroad.com). This month I'll go into further detail of getting the front suspension and steering to fit whether the suspension is at full droop, ride height, articulated, or completely compressed after coming off a too-much-throttle/not-enough-brains jump. Come back in a few months when I'll show you more of our geartrain, which should stuff plenty of options (and shifters) within reach of the driver's seat, and how to correctly install rear leaf springs. 2. The Dumpster's front suspension is a three-link with a Panhard (track) bar. Most factory Panhard bars are of fixed length, such as this Dodge Ram 1-ton version I'm using. Because it is not adjustable, I needed to make sure the axle is centered at ride height. I did this by measuring from the frame to the top ball joints when the axle was exactly 51/4 inches from full compression. As the suspension compresses the axle moves toward the passenger side 1.18 inches. As it droops it moves slightly toward the driver's side 2.81 inches along the arc of the Panhard bar.2. The Dumpster's front suspension is a three-link with a Panhard (track) bar. Most 3. Mounting the Panhard bar to the frame and the axle also requires installing the steering box, draglink, and tie rod simultaneously. Try to run the Panhard bar and draglink on the same slope and attach in nearly identical points along the frame and axle. This way they move along the same arc and reduce bumpsteer. Bumpsteer occurs when the movement of the suspension causes the front wheel to turn due to improper geometry. Since the draglink attaches to the tie rod, I made the Panhard axle mount behind it when the wheels are pointing forward.3. Mounting the Panhard bar to the frame and the axle also requires installing the s 4. I am using a Scout steering box from PSC Motorsports that has been reversed to push the box forward away from the suspension parts. To determine the proper pitman arm length, I measured from the ball joint to the tie rod mount on the steering knuckle (A). If the pitman arm's sector-shaft-to-draglink-end length (B) is greater than A, the steering will be fast, but there is added stress on the box. If B is less than A, the steering is stronger, but slower. After seven different pitman arms I ended up with a nearly flat pitman arm from a Ford steering box I found at a junkyard that is just short of the knuckle length and clears the frame perfectly.4. I am using a Scout steering box from PSC Motorsports that has been reversed to pu 5. Getting the draglink to work with the late-model Dodge tie rod was a little more difficult. The draglink uses high-angle, heavy-duty tie rod ends from Parts Mike that attach to the passenger side of the tie rod. The tapered hole on the tie rod and pitman arm needed to be opened slightly to better fit the tie rod ends. Then everything was test-fit at full suspension compression and full articulation to be sure it would clear and steer.5. Getting the draglink to work with the late-model Dodge tie rod was a little more d 6. Another constant test is tire clearance. The Dumpster has a set of 39-inch BF Goodrich Krawler tires left over from the Fun Buggy. These rub the control arms slightly at full turn, but adjusting the steering stops will easily fix it.6. Another constant test is tire clearance. The Dumpster has a set of 39-inch BF Goo 7. By mounting a tube vertically in the lower shock mount at ride height and then seeing how far it moved side to side during articulation, we found that the axle moves almost 4 inches total from side to side through the axle travel. Mounting the Icon Vehicle Dynamics shocks nearly vertical at ride height allows them to move slightly side to side during articulation without hitting the coils on the frame.7. By mounting a tube vertically in the lower shock mount at ride height and then se 8. Because the Icon coilovers have an additional EVS jounce bumper on the shock shaft, we couldn't measure the shocks at full compression. We had to find out exactly how short they will be under full compression from Icon. This told us where the upper shock mount should be from the axle mount at full compression, and then we were able to locate and start building the shock hoops.8. Because the Icon coilovers have an additional EVS jounce bumper on the shock shaf 9. To mount the shocks to the hoop, Pacific Fabrication made tabs that slide over the shock hoop tube and can then be fully welded. Small Poly Performance reservoir mounting tabs will be added, as will shorter reservoir hoses. The shock hoops are designed to fit under the original fenders, so from a distance the old bodylines are uninterrupted. Unfortunately the custom dual-rate coil that Icon supplies for Ford Super Dutys is too heavy a rate for the lighter M37 and lifted it 4 inches above the desired ride height, so we'll finish adding the weight of a winch, wiring, and plumbing before we determine exactly what coil springs we need.9. To mount the shocks to the hoop, Pacific Fabrication made tabs that slide over th 10. Pacific Fabrication built a crossover tube to support the shock hoops above the engine. This tube will be cut and tabs added for future engine removal, and more gussets will be added just inside the coilover from the frame top to the crossover tube. And before you ask, yes, it does fit under the hood and above the engine just perfectly.10. Pacific Fabrication built a crossover tube to support the shock hoops above the 11. To install the steering column and wheel, we used universal steering joints from Poly Performance and PSC Motorsports for the 3/4-inch solid bar that runs up to the firewall. This bar easily clears the shock hoop on all points.11. To install the steering column and wheel, we used universal steering joints from 12. At the firewall a tube supports the 3/4-inch steering shaft up to the steering wheel. Inside the tube is a bronze bushing to keep the shaft from flopping around.12. At the firewall a tube supports the 3/4-inch steering shaft up to the steering w 13. Behind the firewall a plate with a tube clamps the outer steering column tube in place and bolts to the firewall. The driver gets a giant old-school GMC truck steering wheel I found at a junkyard. I figure the GMC wheel goes perfectly with the GM powerplant under the hood.13. Behind the firewall a plate with a tube clamps the outer steering column tube in SOURCES Poly Performance 245 Tank Farm Road Units L & M San Luis Obispo CA 93401 805-783-2060 www.polyperformance.com Parts Mike N/A AK 530-885-3850 www.partsmike.com BFGoodrich Tires P.O. Box 19001 Greenville SC 29602 877-788-8899 www.bfgoodrichtires.com PSC Motorsports 11468 FM 730 South Azle TX 76020 817-270-0102 www.pscmotorsports.com Icon Vehicle Dynamics 1580 Commerce Street Corona CA 92880 951-272-4266 IconVehicleDynamics.com Pacific Fabrication 235 Tennant Ave. Unit 2 Morgan Hill CA 95037 408-250-1772 www.pacificfab.net By Fred Williams Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!
