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Steering

By Jeff Zurschmeide


Steering accounts for about half of your experience driving a restored car. Whether the suspension is hard or soft, whether the engine is powerful or meek, whether the seats are comfortable or Spartan, the driving experience is most powerfully informed by the way the car steers. Good steering is key to enjoying your finished car, so you want to get it right.

Restoring your car’s steering system goes hand in hand with your suspension restoration, and in fact the two systems are most often restored together. As with your suspension, all hard steering parts must be crack-checked using ultra-violet light (often called “Magnaflux” crack checking) before they are returned to your car. Cracked components may be repairable, or they may need to be replaced.

A special case for steering is the steering box or rack. These components are prone to wear and may or may not be adjustable. There are several designs for steering boxes, such as “worm and sector gear,” which is also known as “recirculating ball.” Another design is known as “cam and lever.”

In all these designs, rotating motion from the steering wheel is fed into a system of gears and ball bearings to swing an output arm (called a Pitman arm) through an arc. Steering rods are attached to the end of the Pitman arm and used to turn the wheels. Sometimes, an additional Pitman arm and bearing case (known as an idler arm) is used on the opposite side of the car as the steering box. This allows the car to have two equal-length final steering rods and a central rod between the idler arm and the steering box.

All steering box designs use interacting moving parts, and they tend to loosen up as they wear. You experience this wear as increased play in the steering wheel. Some steering boxes are adjustable to account for wear, while others are not. Rebuilding a steering box is generally a job for a professional, as the play between gears and other components must be set precisely, and bearings generally must be pressed into place.

Sports cars and British imports are more like to have rack and pinion steering. This design is much simpler than steering box designs. The steering wheel turns a small gear (the pinion) which engages a toothed rod. Since the pinion is held motionless, the toothed rod (rack) moves from side to side. Equal-length steering rods attached to either side of the rack are moved to turn the wheels. Like a conventional steering box, rebuilding a steering rack is generally a job for a professional.

All steering designs may be manual or power-assisted. With a power steering system, engine power is used to turn a pump that applies additional pressure on the steering gear in whatever direction you turn the wheel. The first general market power steering system was introduced on the Chrysler Imperial sedan in 1951, and by the end of the 1950s was standard on most American cars. Foreign automakers came to power steering much later. Like steering boxes, power steering pumps are generally replaced or professionally rebuilt.

Apart from these main mechanical components, there are several steering components that you can and should replace. Chief among these are the tie rod ends and ball joints. Ball joints are used in place of king pins in later cars. They are ball-and-socket joints that allow freedom of rotation to your steering spindles and hubs. They generally come pre-lubricated with a rubber boot over the socket. If the rubber boot is torn, a ball joint won’t last long.

Similarly, tie rod ends connect your steering rods to the steering arm on your spindle/hub assembly. They also use a ball-and-socket joint to allow the steering system to reorient itself freely as your suspension moves through its arc.

As you reassemble, be sure to always use new ball joints and tie rod ends. You’ll be surprised at the difference they make to your car’s driving habits. Also, you’ll notice that tie rods come in left-hand and right-hand threads. This is so that your steering rods will function like a turnbuckle. Rotate the rod in one direction and it gets longer. Reverse the rotation and it gets shorter. This allows you to adjust your wheel alignment without removing one end of the rod.

It’s not obvious, but you can center your car’s steering wheel by lengthening one steering rod and shortening the other by the same amount. If you keep the wheels pointing straight ahead, this will have the effect of moving your car’s steering rack or pitman arm and rotating the steering wheel. When you take your car to be aligned, be sure to ask the technician to straighten up the wheel -they don’t always do that, and it’s part of the “new car” mystique.

Another factor to mention to the alignment technician is if you are using tires of a different design than the manufacturer specified. Most often, this will be a change from bias ply to radial design tires. Your alignment technician may recommend a slight change to alignment specifications for a different tire design.

For a classic restoration, you will always want to replicate the manufacturer’s recommended camber, caster and toe settings. These are designed to provide the best experience in standard road driving. Playing with these settings is used only in high-performance applications, and tends to trade off low-speed driveability and tire wear for better performance.

Dos and Don'ts
Thumb up  DO
  • Replace your tie-rods. If they’re old, they’re worn
  • Set your alignment according to the factory specifications
  • Remember that your classic cannot handle like a new car

Thumb down  DON’T
  • Don’t decide to drive with a worn or faulty steering box
  • Don’t drive hard on tires with much greater grip than the steering components were designed to handle
  • Don’t overtighten worn idler arms, or wheel bearings
The Popular Restorations Project Car
Author photo

1946 Packard: Restoring the Steering

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The Popular Restorations project car’s steering turned out better than expected. At one point I was considering turning the car into a resto rod. That was just after I purchased it and had driven it 600 miles from Sacramento, California to Portland, Oregon. I had noticed the original steering was not very tight and was not confident it ever would be.

I changed my mind after a couple of people told me that Packard steering was among the best in the industry in its time and that the Popular Restorations project car should be fine with new parts.

The steering gear is a Gemmer worm and roller type. The worm rotates in two tapered roller bearings in the steering gear case. The worm meshes with a three-tooth roller which is carried on the cross shaft on needle roller bearings.

The steering linkage is a double-link design, incorporating a cross bar and idler arm with two cross tubes between the steering brackets and Pitman arm to allow independent wheel movement.

I adjusted the cross shaft adjusting screw on the steering box.

And also replaced the tie rod ends, and the idler arm bushing.

The connecting rod has threaded ends that allow you to adjust the tension on the ball joints of the Pitman arm, idler lever, and cross tubes. These were already tight and did not require further service.

As I mentioned in the Suspension article, the car drove straight as an arrow down the freeway even before the alignment. The steering has very little play.

But I must confess that when the car is not moving (e.g., parallel parking) it takes a lot of strength to turn the wheel, even with its huge 18 inch diameter and 5.25 turns lock to lock. I’m not particularly weak but I usually break a sweat if the parking space is at all tight.

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Interview
 

Line-Up Shops, Inc.

By Jeff Zurschmeide

Steve Olson - Shop Foreman
934 SE Sandy Blvd.
Portland, OR 97214
503-234-9797

PR: What are the basic issues around steering and alignment adjustments for classic cars?

SO: For most people with old cars, they’re not driving them daily. They’re taking them out in nice weather and driving it to the show and shine or whatever. We try to get them to where they won’t wear the tires and handle as well as possible.

PR: When you do a steering alignment on a classic car, do you have the specifications or do you just adjust it to a generally good setting?

SO: The older cars had a general setting. They weren’t quite so concerned as they are with modern cars. I was taught to get the wheels standing straight up and down. Then tan old car will handle the best that it can and not wear out tires abnormally.

PR: Are there alignment differences between bias ply and radial tires?

SO: We used to use different settings for different tires in the 1960s and 1970s when radials were coming out. There was a definite camber setting you wanted with each kind of tire. The vertical angle on the bias tires was not as flattened out as with the radials. The radials needed to be flatter to the road surface, and now they’re even tipped in a bit at the top.

PR: Many old steering boxes are worn and loose. What do you do to restore something like that?

SO: You can get the bearings and seals by the numbers most of the time. The two main components inside a steering box that you need to look at are the sector shaft and the worm and tube, which mesh together and have recirculating bearings. If they’ve been worn out or misadjusted, sometimes you just can’t ever get it to drive like you want. So you may have to search. Sometimes you can find good pieces.

PR: How about ball joints and tie rod ends?

SO: You have to do a lot of research. Sometimes if it was a real popular vehicle, you can find them readily available. If the car wasn’t quite so popular, and if it’s really old, I have to do some research and calling around. There are some resources back east that are reproducing old parts.

Recommendations
Click on any item below for more details at Amazon.com

John F. Kershaw, Chek Chart
Automotive Steering, Suspension, and Wheel Alignment
Prentice Hall, Paperback, 2006-04-07
This book correlates to the National ASE Certification Test and the NATEF Automotive Program Standards for Automotive Content Area A4, (Steering and Suspension). Real world examples help users prepare to take and pass the ASE certification test. Accompanying the book is a multimedia CD-ROM that features sample ASE-type questions with answers. The major emphasis is on diagnosis and troubleshooting automotive steering and suspension systems. Along with ASE content, information is included on drive axle shafts, CV joints, and rear axles.

Jeff Killingsworth, Eric Godfrey, John H. Haynes
Suspension, Steering & Driveline Manual
Haynes, Paperback, 1999-01-15

An excellent book on suspension, steering and drivelines for foreign and domestic cars and trucks, front/rear-wheel drive vehicles, and performance modifications.

It has sections on rebuilding front-ends, replacing shock absorbers and struts, overhauling differentials, replacing driveaxles and boots, and improving your vehicle’s ride and handling. Wheel alignment specs are included.

External Links
CarBibles.com has an excellent article on steering.
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