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PSC Motorsports Hydraulic Steering System - Tech

Posted in How To on December 26, 2006 Comment (0)
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The PSC Extreme Duty Cylinder Assist Kit will provide ample steering power for Project Scrambled Adventurer. PSC can assemble steering kits for many 4x4s and custom buggies.

You jump in your Jeep, turn the steering wheel to the left and then right, and the tires and wheels respond to your commands. Basic mechanics, right? But what about all the mechanical components in between the steering wheel and the tires? What's moving around in front of you and below you? Steering systems in some cases are complex in their mechanical designs and layout. Most problems are due to not realizing the importance of proper component installation, usage of quality parts, and regular maintenance. Throw in some extreme off-road conditions, and the factory or poorly set-up steering system may or may not make it to the end of the trail.

The power steering system at a glance is basic, yet in reality it is complex and one of the most important systems on your vehicle. Proper steering system installation is also a major factor in on- and off-highway safety. The complete geometry of a steering system changes when you add lift to the vehicle. Larger tires make the system work much harder. In most cases, the factory steering system doesn't last too long under harsh conditions.

Mounting the PSC gearbox to the AFW custom frame went smoothly. The holes were correctly located, and bolt alignment was perfect. The gearbox is held in place by four Grade 8 bolts.

Most four-wheel-drive vehicles use a recirculating-ball steering gear as the backbone to a power steering system. The system in its entirety includes a gearbox, power steering pump, fluid reservoir, belt or belts, high- and low-pressure hoses, tie rod, drag link, pitman arm, steering linkage, U-joints, column, and steering wheel.

The rotary vane pump runs off of a belt from a pulley on the motor. This pressurizes the hydraulic fluid to power the steering system. It uses retractable vanes that spin inside the pump assembly: The vanes pull hydraulic fluid from the return line into the pump at low pressure and then force it out at a very high pressure from the pump outlet into the gearbox. A small loss in engine horsepower due to belt and pump resistance is one consequence of this type of system, but the assistance offered by power steering over manual steering greatly outweighs the loss.

This is an upward view of the PSC gearbox from inside the frame.

Once the high-pressure fluid makes its way into the gearbox, it forces the gearbox worm gear to move left or right, depending on which way the driver turns the steering wheel. When the worm gear moves, it causes the pitman arm to move the drag link, which is connected to the tie rod. The tie rod is connected to the knuckles at each end of the axle. The result: The wheels and tires move left or right.

If the geometry of the factory steering system is changed, not only is the vehicle's alignment thrown off but the travel of the drag link and tie rod and the way the vehicle steers are also affected. All this can lead to binding and broken components. Oversize tires produce a larger contact patch (footprint) and more rolling resistance on the highway and trail surfaces, which in turn requires more force to turn the tires left or right. These forces can snap weaker factory components. Thus, proper vehicle setup includes heavier-duty components to handle the increases in torque. Ideally, this should also include beefing up the section of frame where the gearbox mounts.

We took all these factors into account when we started Project Scrambled Adventurer's steering system. We chose PSC Motorsports' Extreme Duty hydraulic cylinder assist system for numerous reasons. The company is well known throughout the industry for producing some of the best-quality components and systems available. We have witnessed firsthand the ruggedness and dependable performance PSC hydraulic assist systems offer. We knew the system would endure years of punishment pushing the Scrambler's massive 37-inch Toyo tires around.

Our friend Scott Arntz at Extreme Gear Off Road in Orangevale, California, will be installing the steering assist. Since this is a scratch-built installation, Scott first laid out all the components, took all the appropriate measurements, and then figured the entire steering system's movements, articulation, and proper steering geometry.

When installing this type of system, it is imperative that the proper clearances are taken into account for all moving parts. Routing of the hoses is also critical, making sure they are not rubbing or chafing on any moving components.

Installing the ram requires proficiency in math, geometry, and having a keen eye for all things mechanical. The vehicle's flexing and articulating on the trail means the ram clearances in respect to the tie rod and drag link are critical. This will be included in part two of this steering install.

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Sources

PSC Motorsports
Azle, TX 76020
817-270-0102
www.pscmotorsports.com
Extreme Gear Off Road
Rancho Cordova, CA 95742
877-258-5832
www.extremegearoffroad.com

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