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How to Rebuild a Saginaw Power Steering Box and Hydro-Assist Steering System

13 Tips to Improve Saginaw style and Hydro-Assist Steering Systems

We love tracking down and giving out tips like these tips to improve Saginaw style and hydro-assist steering systems to optimize your power steering system. The job of your 4x4's power steering system isn't an easy one, and the more modified the vehicle, the bigger the obstacle, the harder it is to steer over, though, or around. Turn right, turn left, go straight, it all sounds so easy when you don't know what is actually happening to steer those massive tires down the trail. We've built several Saginaw style steering systems with and without hydro-assist, for a few different vehicles that get use both on- and off- road. Through trial and error and learning from other experts in the off-road industry we've learned a thing or two about assembling parts to make a Saginaw style power steering system that works.

This article is intended to help you maximize the performance of your power steering system no matter what you drive or where you drive it. Sure, some of the parts may seem vehicle specific, but you would be amazed at how much of this technology applies to just about anything with 4x4 and a steering wheel. We're going to stay focused on systems that use a Saginaw style steering box and pump, and give you the best practices formula for keeping your 4x4's steering system happy if you are running bigger tires, a hydro-assist steering, and more.

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There are a few different companies that can help you with your Saginaw style steering system whether what you need is a rebuilt box, high-performance pump, or if you need to add a steering ram for ram assist. One company that we've used again and again is West Texas Offroad and their line of Redneck Ram products. They can rebuild, add ports for a ram, or reconfigure some steering boxes (by adding reversed internals for forward sweep Saginaw boxes) and will even recommend a box when you have a custom build, as we often do. This is a right-hand-drive JK steering box that West Texas Offroad recommended and prepped for our past two UA builds. The box can be mounted outside the framerail, and believe it or not, there are a fair number of right-hand-drive JKs in the U.S., sold to folks who work for the rural U.S. Postal Service.

This is the pump off of our Cummins R2.8L turbodiesel in the Derange Rover that had the temerity to die. Power steering pumps seem to get smaller and smaller but continue to push enough fluid to power boxes, rams, hydro-boost, and more. Still making sure that you have a large reservoir close to the inlet of the pump and with as large an input line as possible will keep these hard-working parts happy for years to come. We mistakenly tried to route the input line from the opposite side of the engine to the pump when the Rover was first assembled. The end was premature power steering pump death; the solution was to replace the pump and move the reservoir closer to the pump to ensure the pump won't starve for fluid when working hard.

Older style "canned ham" Saginaw style power steering pumps can be modified or "hot rodded" to increase at idle pressures and flow. To do this, remove the high-pressure fitting at the back of the pump. It may be accompanied by a spring and flow piston it holds in place within the pump (and a bunch of fluid if your system is otherwise intact). With the fitting removed, drill out the orifice of the fitting to 5/32nds, clean up any metal bits, and reinstall.

Here's how the parts go back into the rear of the power steering pump. The spring goes into the pump first, then the flow piston with the nut toward the spring. Last, the "hot rodded" high-pressure fitting is threaded back into the body of the pump.

Keeping power steering fluid cool is also a must. It gets heated up by the pump and as power steering lines pass by hot engine components. Just like with any fluid, heat is bad and causes the fluid to thin and lose its properties that are essential to proper power steering function. You generally want to run a fluid cooler like this one from Flex-a-Lite on the low-pressure "return side" of the power steering box. That way it gets a chance to cool before going into the reservoir and back to the pump.

Adding a filter to any power steering system is a good idea. The benefits of a filter are at least twofold, with the first benefit being obvious: removing trash from the system. The second benefit is that a filter will allow for more fluid volume, which is better for preventing fluid starving and requires more heat to heat up. This Wix filter (PN 58593) was recommended to us by our friends at West Texas Offroad. The part is intended to filter the transmission fluid on some econobox cars, but it's great for power steering systems because it not only includes a mesh filter but also has a magnet around the circumference of the filter body. The magnet grabs any iron-based debris while the mesh grabs non-ferrous metals and other trash that may find its way into your power steering system.

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Another way to get the most out of your power steering system is to make sure that the fittings you are using have consistent and large openings. The specifications for different fittings like these two -6 AN fittings can vary. Smaller holes through fittings will restrict fluid flow.

We like to use rebuildable high-pressure side power steering hoses because we've seen our fair share of hoses blown apart on the trail when the swedge wasn't quite right. If you're out on a trail without a hydraulic swedging tool, you're literally hosed (and no one carries those on the trail). Rebuildable hoses can be rebuilt if they come apart, or you need to repair a damaged hose, and there's enough length to get past the damage in the hose or a spare piece of hose.

On the low-pressure side of the system (and most low-pressure fuel systems) we like to use pushlock style hoses. Occasionally we have cussed and damned pushlock hoses and fittings when they just don't want to go together. The trick seems to be to use quality parts, a little fluid as a lubricant, and we found that this inexpensive tool from Summit Racing can help force home some of those stubborn fittings in pushlock style hoses.

Sadly, not all power steering fluids are created equally. We sourced some Swepco 715 in 32oz. bottles from Summit Racing for a few of our more high-performance power steering systems. Swepco isn't exactly inexpensive, but it has anti-foaming properties that help prevent cavitation, which can kill pumps and make your rig not steer when you want it to. This fluid also provides consistent properties at a range of normal operating temperatures.

Steering systems also have to be mechanically optimized to work well and not cause damage to themselves. We learned the quick and dirty method for this from our pal and head fabricator at Rob Bonney Fabrication, Rob Bonney. The general pattern is to see how far the pitman arm end of the drag link will need to turn right and left so that the knuckles hit the steering stops both ways. You'll want to measure this distance parallel to the centerline of the axle. It might be something like 7 inches total, 3.5 to the right and 3.5 to the left. Then you want to find the spot on the pitman arm that moves whatever your distance is plus about 1/2 an inch. For our example, the point on the pitman arm that will move the pitman arm end of the drag link is about 7.5 inches in total, 3.75 to the right and 3.75 to the left.

The idea is that the steering stops on the knuckles bottom before the steering box runs out of throw. You can cheat this number down closer to a 1:1 ratio, but it's best to overshoot a bit. You never want to have the steering get into a situation where the tires force the steering box farther than it's mechanically designed to go. You can also adjust the steering stops to prevent this if it's going to be an issue on your rig. Test it before going out on the trail, or it may cause a catastrophic failure.

You also have to test the system to make sure that your suspension flex, droop, and compression are not maxing out your steering's tie-rod ends. Each tie-rod end (and even rod ends) will only allow so much movement before binding. If they get into a bind, then the length of the tie rod or drag link will act like a pry bar trying to pull the tie-rod end or bolt passing through a rod end apart. Since these "pry bars" are long, they can do a great job of ruining your steering fast. Broken steering is very bad, so extra care must be taken to ensure all the parts work as they should as the suspension cycles. Shown is a show truck from SEMA where the rod end is in single shear (that's bad) and is just about maxed out in terms of angularity. Drooping out this suspension could cause a steering failure. This could easily happen on-road or on a trail (although this truck would probably never be on a trail).