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Keeping You in Suspension

Restomod tips for a classic car

It was love at first sight, the sleek lines, the shiny paint. Underneath the hood sat a powerful engine, and the interior fit you like a comfortable pair of three-year old sneakers. And when you test-drove your dream classic, the car you had always wanted in high school, it felt perfect. A few quirks, but that's what makes owning a classic car fun, right?

Hidden Problems

Well, now that the honeymoon is over, all of the things you once thought were endearing are becoming annoying. You start to notice the clunks and rattles over every bump. To make things worse, it goes around corners like a Yugo on stilts. Mysterious things are happening to the underpinnings of your beautiful car.

Initially it might be easy to overlook a problem in the suspension of an older car. The suspension is hard to see and sometimes a problem is only apparent at high speed or under load. If you are contemplating the purchase of a restored classic, keep in mind that you may not notice a problem right away on a test drive.

We'll take a look at some of the components that you might need to replace. Along the way, we'll also try to improve on a few things that will add even more enjoyment to your ride. All of the handling symptoms mentioned above point to the need for a complete restoration of the suspension, and possibly some mods as well, hence the term "restomod."

Some people might think only of shock absorbers when they hear the word suspension, but this actually refers to the entire system that supports the weight of the car. Think of the amount of stress and strain that these components go through. Almost all of the weight of the car has been supported by the suspension for decades. Really, this is an amazing feat. If your resto vehicle is a sports car, or an American musclecar, the stresses of spirited driving and great amounts of power have no doubt added strain to the suspension.

So what are some of the components that wear out? Obviously, the shock absorbers are a wear item, as they have to soak up and smooth out all of the unevenness in the road. Springs are the actual load supporting parts, and as you can imagine, they often lose their tension and start to sag lower and lower as the years drag on. If you have a car with a ladder-style frame, there are rubber mounts that attach the car's body to the frame members. If these are loose or rotten, it will contribute to some odd handling as well.

Replacement Musts

Two major and often overlooked parts of the suspension are the bushings and ball joints. These are rather inglorious little parts that isolate the pivoting and moving suspension pieces from other components. They include tie-rods, which are the final link from the steering to the wheels.

Bushings and ball-joints are designed to wear out, thus protecting more expensive parts. All of the bushings and ball joints on which the suspension pivots must be in near-perfect condition. A loose ball joint, or a worn-out bushing or tie-rod, will not only hinder the cars handling, but is downright dangerous. Consider it a must to replace these even if they look good.

Now, what about improvements? Many older vehicles that are popular restoration projects have stock replacement parts, as well as performance upgrades available. Oftentimes, a major improvement can be gained in using these parts. Bushings will have a harder rubber (or polyurethane instead) that lasts longer than the original material, and deforms less under load. Shocks, ball-joints and springs have all benefited from improved technology.

Another major upgrade can be made with a device called a sway bar. Contrary to how the name might sound, this device actually limits sway, or sideways lean as a car moves through a corner.

You may have noticed that some cars lean alarmingly far as they go around corners. When the vehicle is in this position, you can see that the suspension on the outside of the curve is nearly bottomed out, or compressed as far as it will go. However, the suspension on the inside has very little weight on it, so it is hanging, almost topped out at its travel limit. The sway bar will even things out some, causing the vehicle to lean over less dangerously, and distributing weight to all tires. This is a huge advantage in the handling of the car.

Stabilize Sway

When viewed from the front or rear of the car, a swaybar is usually shaped like a very wide "U" (sometimes laying down flat), and is attached to the suspension on both the right and left sides. The center portion of the "U" attaches to the frame of the car. A swaybar is made of hollow tubing, and its diameter determines the stiffness or resistance to body roll.

As a car rounds a corner, the suspension moves up on one side and down on the other. This twists the sway bar up on one side and down on the other. The spring steel that the bar is made with resists this motion, adding some spring tension to the outside wheel that is being compressed, and reducing tension to the inside wheel that is being extended. This dynamic allows the car to remain more level through corners.

Many cars through the mid 1960s have a sway bar on the front suspension. They are much less common on the rear. A bar can be added to the rear to help stabilize sway and movement in the rear through hard corners. The front sway bar can be upgraded to a thicker and, thus, more stiff unit, if the bar does not seem to limit the lean of your car as you would like.

Sway bars can be added to vehicles that never had them to start with. Be careful about adding too much of a sway bar to either front or rear of the car. Balance is important. If the car tries to roll at one end, but is meeting with resistance to roll at the other, it is possible to lift one of the wheels off the ground. As you can imagine, this will cause some traction problems. Buying adjustable swaybars can help you to fine-tune these aspects.

Our next article in this series will show some upgrades and installation processes, using a 1972 Porsche 914 as an example. All of these principles can apply to any car, so stay tuned. By adding the correct combination of parts, a restoration project can be made to handle like new, or even better than new.