Rack-and-pinion steering is somewhat different from the steering boxes we looked at in last month's issue. Perhaps the best way to describe it is that it combines the steering box and tie rod, or centerlink, into one unit. It also mounts up front, across the car, either behind the axle centerline or in front of it. This is why you'll hear steering racks referred to as frontsteer and rear-steer racks. Mount a rear-steer unit in front of the axle centerline and the wheels will go left when you steer right, in exactly the same way some steering boxes need to have their internals reversed to work in certain situations.
The steering wheel, through the steering column, is directly connected to the rack, though it may also employ universal joints, a rag joint, or a sliding joint. Inside the rack is a pinion assembly that in turn moves a toothed piston, and this operates the steering gear. The tie rods are connected to each end of the piston.
The advantage of rack-and-pinion steering is that it is more precise than a steering box. There are fewer moving parts, which makes the steering more responsive. Of course, as with boxes, there are the options of manual or power steering. It's also very easy to mess up your frontend geometry when adding a steering rack to an existing frontend, resulting in bumpsteer, though of course this will be eliminated if you opt for one of the many rack-and-pinion retrofit kits we'll go into shortly.
Probably the most used rackand- pinion in hot rodding is the Mustang II unit, if only because the MII IFS, or an aftermarket version thereof, is the most widely used independent frontend, fitting perfectly under most early body styles width-wise.
If a conversion kit is not available for your car and you want to fit a rack-and-pinion, you may be able to fit just a steering rack, or you may opt to change out the whole front suspension. It all depends on the original frontend's geometry and whether a rack will physically fit. If you intend to just swap the rack, there are a few things you should bear in mind if you want your finished car to handle and steer correctly.
We covered bumpsteer in our Geometry Lessons" article back in the October 2007 issue, which explained why the correct location of a non-stock-application steering rack is critical, but we'll briefly recap for those who were asleep at the back of the classroom. As an independent front suspension (be it A-arms or McPherson strut in design) moves up and down, the wheel moves through an arc, pivoting about the lower control arm's inner mounting point. A farther arc is defined by the outer tie-rod end, pivoting about the ball joint inside the steering rack. Where these arcs differ, the tie rod will cause the wheel to move inward or outward, meaning the car will "self-steer" when traveling over bumps, hence the term bumpsteer.
To eliminate the problem, mount the steering rack so the tie rods are parallel with the lower control arm, and-perhaps the most difficult part, as it may involve searching for a particuar-width rack, though custom-width aftermarket racks are available, as we'll see-ensure that the inner pivot point of the control arm and the ball joint inside the steering rack, at the inner end of the tie rod, are the same distance from the chassis centerline. As you can see, the rack will have to be a specific width between the ball joints and mounted in a specific place to work correctly, which is why it is simply impossible to mount a steering rack in some cars using stock suspension. This is where the aftermarket kits come in, though unsurprisingly, they are mainly available for the most popular cars.
Manual Racks
Need a manual rack but can't find one that works in a rear-steer configuration, or is everything you source simply too wide? Then one of Flaming River's custom-made racks could take care of the width issue, with four widths in stock and custom sizes available. The same company's rear steer rack could be the answer to oil pan clearance issues or simply where you need a rear-steer application. There's also a front-steer rack based on the '74-78 Mustang II design for a wide variety of IFS street rod applications.
Maybe you're a billet junkie? Then check out Flaming River's Straight Arrow billet modular rack available in front- or rear-steer configuration. Custom pinion lengths and pivot points are available as well as more than 20 different inner tie rods and several ratios. All that and it's available in left- or right-hand steer, and with standard pillow-block or Mustang II-style mounting brackets.
Power Racks
If you're just after a power rack-and-pinion, not a kit, Flaming River can help you with its new street rod and aftermarket power rack. Gun-drilled for improved performance, it features a unique multiple mounting position and a finned billet pinion housing as well as a chromed tube and aluminum casting. Based on a '74-78 Mustang variablepressure power rack, it'll work with Mustang II suspensions. Rear-steer GM styles are available, too.
AGR Performance can also hook you up with a power rackand- pinion, offering Mustang and hot rod racks with an optional chrome finish, as can Unisteer, with replacement racks for numerous vehicles, as well as custom front- and rear-steer racks.
Tri-Chevy
Perhaps the obvious first choice for a power steering rack conversion, owing to the popularity of the cars, is the '55-57 Chevy. Speedway Motors, CPP, and Flaming River all offer a bolt-in conversion kit, which involves unbolting the original steering box, idler arm, and tie-rod assembly and bolting the new bracketry in place using existing holes. The Speedway version includes tie-rod ends and special fittings that accept AN-style hose ends, and it can be used with most GM power steering pumps. However, it will only fit '55-57 Chevys with small-block engines that have chassis headers and stock-type pan sumps. The necessary universal joints and other parts to hook up the kit are also available from Speedway.
The CPP kit is available in both manual and power versions, and is also a true bolt-in kit. It features a custom-built Saginaw rack-and-pinion that is narrow enough to match the original steering geometry for zero bumpsteer. The standard power kit includes the rack-and-pinion, brackets, outer tie-rod ends, steering arms, and 6 AN line fittings. CPP also has lower column bearing kit to allow the stock steering column to be used with rack-and-pinion.
Flaming River's entry in the bolt-in Tri-Chevy rack-and-pinion market consists of either manual or power racks on a bolt-in cradle, with a number of options from just the rack and cradle, to a comprehensive kit that includes absolutely everything required: the rackand- pinion, cradle, universal joints, power steering pump, bracket and pulley, polished aluminum reservoir, tilt column, swivel floor mount, and all mounting hardware.
You really do have a great choice of bolt-in conversions for your Tri-Chevy, as Eckler Industries and Unisteer also offer such kits. Eckler offers a number of kits, to be precise, depending on whether you have a small- or big-block or want to run a stock steering column or aftermarket tilt column. Eckler's kit works with your Chevy's stock outer tie rod ends and sleeves, the rack-and-pinion mounted in a rear steer configuration like the original setup. This kit does require some exhaust modification, though Eckler can supply headers to rectify this. Unisteer's kit uses a modified Saginaw power rack to geometrically match the stock steering, and comes with the rack, outer tie-rod ends, steering arms, -6 AN banjo line fittings, brackets, and mounting hardware. The bracketry mounts to the existing steering box and idler arm chassis holes. If your Chevy has clearance for the factory centerlink, then you should have clearance for Unisteer's Tri-Five rack.
'55-57 Thunderbird
Flaming River offers a similar setup to its Tri-Five kits for the early T-bird, again complete with everything needed, and with a tilt column that will accept either a stock or aftermarket steering wheel. The difference between the Tri-Five kit and the T-bird is the use of Flaming River's Travel Bar, which connects new tubular inner tie-rod ends at the original pivot points, reducing bumpsteer. The Travel Bar is similar to the versions used on the company's later-model Camaro and Chevelle steering systems. Again, there's no fabrication required, and no welding. This is a bolt-in deal.
Cross Steer
It's not often a completely new product comes to market where it seems the solutions have all been found, but the electronic power steering in our last issue is a case in point, as is the Cross Steer rack-and-pinion shown here. Manufactured by Unisteer and also available through Speedway Motors and CPP, this innovative product is designed to replace a Vega steering box in a cross-steer configuration. This rack-andpinion assembly has a long passenger-side tie rod that connects to the right-hand spindle where the Vega drag link would normally fit. The unit mounts to a bracket that bolts to the existing Vega box mounts, with brackets to suit.
The Cross Steer rack is available in a New Build Kit or a Retro Kit, the latter for those wishing to replace a Vega box, and as such is supplied with a coupler and a section of shaft to hook up the column. The Cross Steer is available for '28-34 Ford frames, though CPP also offers a version for '35-40 frames, with a slower ratio for easier steering. This only works with stock or 2-inch dropped axles, though.
'54-64 Fullsize Fords
Love your '54-64 Ford but hate the steering? You're not alone, which is why Rick Wurth of Wurth-It Designs introduced a bolt-in rackand-pinion conversion kit that uses stock frame holes. Available either with replacement tie-rod ends and steering tubes, or using the drag links and tie rods already on your Ford, the kit offers 3 1/2 turns lock to lock with a rack available at any auto parts store, and will accommodate Ford engines with a front-sump oil pan. The kit includes everything to install the rack-and-pinion, including an intermediate steering shaft and U-joints and metric to -6 AN hose fittings to connect the rack to the power steering pump.
Oddities
As it seems that anything goes these days and customs are based on increasingly later-model body styles, we've included a few applications for later '60s and early '70s cars. Unisteer can supply a rack-and-pinion kit for small- and big-block A-body Mopars, as well as the '62-67 Chevy II, while Flaming River can sort you out if your pride and joy is a '61-72 Chevy II or Nova. Maybe you have an '82-95 Chevy S-10 chassis under your rod or custom? Well, Unisteer can help you out with a rack-and-pinion conversion for just such an application. A 1960-65 Falcon or Comet light your fire? Then call Unisteer for one of its conversion kits, either power or manual, black or chrome.