Part 10: We Add Rear Steering To Our Dana 80
To begin, we had to figure out where we were going to mount an additional power steering pump. We wanted the rear steering system to be completely separate from the front hydraulic steering setup. We didn't need or use the Titan's factory A/C compressor any longer, so naturally its position on the lower driver's side of the engine was a good place to start. Lavender removed the A/C compressor from the vehicle and took some measurements to see if a TC-style power steering pump would fit. After performing a little math, Lavender figured that the position was actually an ideal mounting location considering the necessary pulley size and plumbing access. Lavender turned to his computer and started designing a new mounting bracket using Solidworks, a three dimensional design program that makes fabrication of such parts much simpler.
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While on the subject of Heim joints, we wanted to showcase a product that we feel has received little recognition until now. Evolution Machining & Fabrication is a small company located in Calgary, Alberta. Owned and operated by former TTC champion Clay Kraatz, Evolution builds products for extreme use. Check out the Evo Heim joints, or Evo rod ends, as some call them. We've used Evo joints exclusively since the very beginning of the Mega Titan project. We like them because of their super-indestructible design attributes. Each joint begins life as a large chunk of billet 4140 HTSR steel. After several hours on a CNC mill, the extreme-duty housings are ready to assemble as a joint. First, though, each is treated to a durable zinc coating to prevent corrosion. Each joint has a few proprietary internal parts that contribute to overall strength, and each is both greasable and rebuildable. Evo joints are available in a variety of sizes and are competitively priced, thanks to low overhead and a very niche product portfolio.
To steer the rear tires on the Mega Titan, we sourced two Bomb rams from Evolution Machining & Fabrication. Appropriately named because they looked similar to pipe bombs, these rams are specifically designed for large tire and high-weight applications. Kraatz sent us two single-ended rams that could easily handle the needs of the Mega Titan. Each features a 3-inch microhoned tube body with a .250-inch wall thickness. The end caps are made of T6061 aluminum designed with a trick spherical dome that allows more than half the surface area of the piston to be utilized when the ram is completely bottomed out. We like this design because it allows more force and a quicker reaction from the steering-locked position. These rams come with Polypac seals that are rated at 5,000 psi and feature dual rider bands to help keep rod deflection to a minimum. Each hose fitting is threaded into the end caps, not welded to the tube, thus eliminating any potential warping. The rod is made of 1.50-inch induction-hardened-steel, and the ends are drilled and tapped to accept 3/4- or 7/8-inch hardware. They have a working pressure of 1,600 psi, which translates into a working force of 5,000 pounds on the rod side and 7,900 pounds on the piston side. We especially like the fact that these single-ended rams can be changed into double-ended rams by simply replacing the aluminum cap and adding another rod. Bomb rams are available in 8-, 9- and 10-inch stroke lengths.
To control our rear steer, we opted to use a PSC Motorsports Competition Rear Steer Pilot Valve. Essentially, this valve provides joystick control of the rear steering. We like how the joystick is spring- loaded, because it lets the valve go back to open center when joystick is released. This gives the operator a positive feedback feel. This valve will not return your axle back to center by itself, but rather lets you control with spring-assisted precision just how much rear steer you apply. Simple to plumb, this valve features four -6 JIC ports. Lavender supplied pressure in from the pump, a return hose to the reservoir, a hose to the left turn ram, and another to the right turn ram. The whole setup was pretty self-explanatory once we sat down with the product in hand. PSC also supplied us with a whole assortment of JIC fittings, pressure and return hose, as well as two large power steering coolers to mount in front of the radiator.
PSC Motorsports also provided us with a great-looking remote-mounted power steering reservoir. The 8-inch-tall spun aluminum reservoir features a 3.5-inch diameter with a single internal baffle to help minimize fluid sloshing. A trick billet aluminum mounting clamp and vented cap were also included. Lavender mounted this unit on the passenger-side shock tower at the highest possible point in the system. This mounting method should help prevent aeration while the system is operating at extreme angles.