Original equipment chassis parts on late-model cars and trucks are supposedly engineered to go 150,000 miles or more. But is that 150,000 miles of highway driving on nice smooth roads or 150,000 miles of bumps, potholes and rough roads? The OEMs say it’s some of both.

Nobody can predict exactly how long a chassis part will hold up in use because there are so many variables that affect the life of the part. Washboard roads that give the suspension a pounding, wet weather and exposure to road salt are obviously harder on steering and suspension components than smooth roads and a dry climate. Who makes the parts is also important. Some chassis parts suppliers have a better reputation for durability than others. It also depends on how robust the OEM wants the part to be and how much money they are willing to spend for the part.

In the real world, most chassis parts hold up pretty well in spite of all these factors. A lot of vehicles end up in the salvage yard with many of their original chassis parts still in place. That doesn’t mean these parts are not worn because many of them are. It’s just that chassis parts are often overlooked.

More often than not, ball joints, tie rod ends, idler arms, control arm bushings, springs, shock and struts are not replaced unless they are in really bad condition or have failed completely – and that’s dangerous because the separation of a ball joint or tie rod end can have serious consequences. A ball joint that fails will allow the suspension to collapse. A tie rod end that pulls apart will cause a loss of steering control.

One of the first things an alignment technician does before he checks wheel alignment on a vehicle is inspect the chassis. He checks ball joint play, the tie rod ends, the idler arm (if equipped), the steering gear, control arm bushings, shocks, struts and springs to see if any of these parts need to be replaced. And if any problems are found, he’ll inform the customer that the parts must be replaced before he can proceed with the alignment – otherwise attempting to realign the wheels will be a complete waste of time and money.

SAGGING BAGS

When electronic suspensions with air springs were first introduced 20 years ago on the Lincoln Continental and Mark VII, few people would have imagined that someday this new technology would create a booming business for servicing air ride suspensions. But it has, and it’s a market that shows no signs of deflation anytime soon. Here’s why:

Air springs and electronic ride controls provide a cushy, boulevard ride, but the ride doesn’t last forever. All air suspensions share a common vulnerability: air leaks. And when a system can no longer hold air, it goes flat.

The undercar environment is a harsh one that’s exposed to road splash, salt and debris. Rubber loses elasticity as it ages, becomes hard and eventually cracks. After seven to 10 years of service, many of these older systems start to develop leaks that allow air to escape from the system. The same thing can happen to plastic air lines. Wiring connectors, solenoids, compressors and height sensors are also vulnerable to corrosion and vibration, which over time may lead to failures that disrupt the normal operation of the air ride system.

Now comes the good part (or the bad part if you’re the vehicle owner.) When an air ride suspension system goes flat, it can be very expensive to fix. OEM parts are expensive and may not even be available for some of the older applications. Reman OEM electronic air struts and compressors can provide a more cost-effective alternative for those who want to retain the full functionality of their air ride suspension. The other option is to replace the original air springs and/or electronic struts or shocks with an aftermarket conversion kit that includes conventional coil steel springs with ordinary struts or shocks.

Aftermarket conversion kits for the older cars with air ride suspensions have become a hot item in recent years because the kits provide a repair solution for vehicles that might otherwise be too expensive to fix. For example, a set of four new OEM air struts and a compressor for a 10-year-old 1994 Lincoln Continental retail for around $3,500. Add in the installation labor, and it adds up to a lot of money to spend on a car that is worth maybe $2,500. The same car could be converted to a regular coil spring suspension for around $500 to $600 in parts, and it would probably be a lifetime repair (no future air leaks, compressor failures or electronic glitches to worry about.)

On a Lexus, the numbers are even higher. The OEM air struts list for $1,100 per wheel. If the compressor also needs to be replaced, the parts bill alone is around $5,800. By comparison, a conversion kit for this vehicle typically sells for less than $800 and includes struts for all four wheels.

Vehicles that are equipped with air ride suspensions include Lincoln Continental, Town Car, Mark VII and VIII, Ford Crown Vic, Mercury Grand Marquis, full-size Chevy, Buick and Oldsmobiles, Cadillac Deville, Seville and Eldorado, various Chrysler models, Dodge Dynasty, older Jaguar models, Land Rover, Range Rover, Lexus, Lincoln Navigator, Ford Expedition and Ford F250 pickups, and Mazda MPV.

CHASSIS PARTS OPPORTUNITIES

Though most steering, suspension and ride control parts are sold after an original part has worn out or failed, you don’t always have to wait for a failure to make a sale. There’s a growing market for chassis upgrades, especially in the sports compact car segment.

Coil-over conversion kits for lowering Hondas and other cars of this type have become a popular bolt-on upgrade for street performance. So too are high-pressure adjustable gas monotube shocks, oversized sway bars and stiffer bushings. Complete performance suspension packages with lowered springs and matched shocks or struts are often the best way to upgrade a vehicle. There’s also a strong market for suspension upgrades with SUV and truck owners too. Variable-rate springs, overload springs, helper springs and air springs are all add-on items that can provide the extra stiffness needed to handle oversized loads.

For those who seek adventure off-roading, there are lift kits, multi-shock kits, air lift kits and beefed-up chassis parts to improve both ground clearance and durability.Waiting for a customer to wander into your store and ask for such products is not the best way to market suspension upgrade products. Having a display of such items not only makes customers aware of the products, but encourages them to ask questions – which often leads to sales.

The same goes for ordinary steering and suspension components. One store we visited recently had a simple pegboard display of badly worn and broken ball joints, tie rod ends and a couple of photos of a rolled SUV and a car that had hit a guardrail because a tie rod end broke. A sign on the pegboard read, "Don’t let this happen to you! Replace worn chassis parts now!"

This might be a bit dramatic, but it’s effective. Iit makes people think about the possible consequences of postponing needed chassis repairs.