Modified Mustangs & Fords
Randall Rack Power Steering System - A-Rack-Naphobia
Randall's Rack and DVS Restorations Take the Fear, Frustration, and-Dare We Say It-Bumpsteer Out of Our Rack-and-Pinion Conversion
Faithful followers of Mustang and Fords know that a rack-and-pinion conversion is one of the best things they can do to modernize their classic Ford. But maybe you've found sometimes all is not as it seems-word of mouth complaints, swap-meet conversations, and countless Internet chat-room rants surrounding the conversion have made you squeamish about taking the leap to better steering and handling. Our goal is to show you how and why things work, along with the right way to get your car handling properly.
There are typically four phobias about a rack-and-pinion conversion:
- Will the rack fit?
- Will my headers fit the rack?
- Power-steering pump issues.
- Bumpsteer? More like bum steer.
We'll discuss each of these as we go through our conversion. Our guinea pig is a '70 Mustang convertible that's already had a complete frontend rebuild. The conversion rack system has been provided by Randall's Rack. After installing several different rack systems on different cars, we really like the way Randall's has thought through the complete system, and the company is constantly improving its product. In fact, while writing this article, we got several new toys from Randall's, demonstrating its continuous improvement mindset. Those are the kind of guys we like working with.
Our rack-and-pinion conversion was performed at DVS Restorations in Crawfordsville, Indiana.
Phobia #1: Will the rack fit?
There are several reasons why people run into fitment issues:
Forty years of twists, rust, wrecks, and Dukes of Hazzard-style driving are not kind to these cars. Not only that, but we've seen cars with as much as 11/44 inch of fitment slop from the factory. We've had to beat rack-mounting brackets into cars in the past-not because the bracket was bad, but because the cars were poorly made.
Aftermarket parts are another problem. Big, deep, oil pans are usually the culprit, but other items, such as headers (an entirely separate phobia), braking upgrades, and so on can all cause fitment issues. As enthusiasts, we have to give the rack guys some latitude and understand that it is impossible to design for every aftermarket parts combination, but they should get a decent majority of them.
Poor design. OK, time to put the manufacturers on the line here. We've had stuff that had us shaking our heads trying to figure out what the engineer was thinking. If you've ever installed any aftermarket parts on your car, you have thought this at one time or another.
The Randall's Rack system addresses all the above issues. It uses an adjust-able mounting bracket to adapt to 40 years of frame twisting. The hybrid style of tie-rod system reduces the footprint for parts clearance, and all but the biggest aftermarket parts typically clear. Existing bolt holes are used for the steering gear, idler arm, and crossmember, so there are no conflicts connecting to the suspension or adding additional holes. The only modification to our car was to grind about a 1/4-inch notch on the driver-side engine mount support, which took about 30 seconds. No notching frames, no welding, and it's fully adjustable.
Phobia #2: Will my headers fit the rack?
Selecting the right headers seems to be the really big issue with rack-and-pinion conversions. The reason is that the gear in the rack is towards the middle of the car rather than bolted to the frame. This means you have a driveshaft cutting across real estate that used to be taken up by the headers.
Headers that were designed for the original cars are designed to clear the original steering gear mounted to the frame. Late-model headers won't work because they hit the shock towers and dump in silly places.
If you want headers that fit your rack system, look no farther than JBA's mid-length headers. Having experienced header issues with past rack installs, we were pleased to see how easy it was to install the JBA units and have no clearance issues whatsoever with our small-block installation.
For our application, the midrange header (PN 1650, $500-$650, depending upon material) runs towards the back of the block before angling down, which helps it clear the input for the new rack. Traditional headers start angling down almost immediately, causing a conflict with the steering shaft that's angling towards the steering column. The fact that JBA offers ceramic coating and stainless versions of the mid-length design makes for an even easier decision when selecting headers.
Owners of manual-transmission cars may need to look at clearance issues with the linkage to the clutch, while those with big-block cars already know how much gf a pain headers can be even without changing the steering (you've probably already had to modify the headers to fit, haven't you?). Our advice is to move away from 40-year-old header designs and look for a new one that runs towards the rear of the engine compartment before turning down. JBA can help you select the right header for your project.
Phobia #3: Power-steering pump issues
Most modern rack systems that are used in these conversions are designed for front-wheel-drive cars. Because of this, the pressure that the system works at and the weight of the chassis-and in some cases, the weight load over the front wheels-can have a dramatic effect on the performance of a power steering system. Although it might seem tempting to run out and start making your own rack systems, there is a considerable amount of engineering involved in making these systems work properly for a big-motor/rear-wheel-drive car.
If you're thinking about using your original power-steering pump to save a buck, we'd like you to reconsider. The original Ford pumps are not designed for the correct pressure range on the new rack systems. Although Randall's and other manufacturers will allow you to use the original pump, they don't recommend it because the performance of the rack is reduced due to the mismatch. It's better to use the manufacturer-recommended pump to get the maximum performance from your new steering system.
Randall's offers a modern pump that doesn't require an external reservoir for operation, so it's less intrusive to your engine bay. The company can provide the new pump with a traditional V-belt pulley or a new serpentine pulley for 5.0 conversions. It also offers a complete line of brackets to fit the pump to the old or new beltdrive systems.
Phobia #4 : Bumpsteer
One thing you have to remember about aftermarket parts-just because it fits doesn't mean it's good for your car. We have experienced bumpsteer nightmares with past conversions, so we decided we would not just print a lot of pretties about Randall's rack. We wanted proof that the rack system was a measurable improvement over the stock steering. So we got out our bumpsteer gauge and put Randall's to the test.
Most of the rack systems on the market use a center steer rack with a bar to mount the original-style tie-rod setup to the rack, which keeps everything in the original position (a good thing). This keeps the system from making the bumpsteer issues worse, and allows you to use aftermarket bumpsteer correction parts with your rack setup. Some other conversions are an end-steer design that allows for modern-style tie rods with better range of motion and a smaller footprint.
Randall's setup takes the rack system one step further. It uses a center steer design that incorporates a modern inner tie rod that better places the tie-rod pivot point for improved bumpsteer. We also think the Randall's setup has more range of motion over the stock-style tie-rod system.
When it came time for Randall's Rack to put up or shut up, we were pleasantly surprised with the test results for bumpsteer. We measured the Mustang with both the stock steering and the Randall's steering and found the bumpsteer was reduced to the point that no additional bumpsteer correction was necessary. It's actually below what most racers feel is OK.
Of course, with your suspension setup and parts, and driving habits, you'll want to check bumpsteer on your car, but for this car with a stock rebuild and slight ride height reduction, the numbers came out fantastic. Take a look at what we found.
As you can see on our test vehicle, the Randall's Rack significantly reduced the amount of bumpsteer. Still not good enough for you? For its more performance-oriented clients, Randall's offers an exclusive, fully adjustable center link that allows you to adjust the length of the tie rods and all but eliminate bumpsteer.
We're now at the point where we tell you how wonderful your car will be if you just go buy this stuff. Hopefully, we've gone beyond that and have succeeded in proving to you that with a little information and some data to back us up, your rack-and-pinion conversion can be less stressful and actually improve the feel and handling of your own vehicle.