Solving ride control problems is far more than replacing worn or damaged shocks and struts, and weak or broken springs. Itís first and foremost diagnosis. If we don't spot the problems, we're like the Maytag repairman. We have nothing to fix.

A lot of ride control problems go unnoticed and unrepaired because nobody takes the time to look for them or to diagnose the ride control system properly.

Most of the time, the customer is the one who realizes something is amiss and asks us to check out the suspension. Even so, ride control checks should be included on every vehicle that passes through your shop.

Problem #1:
The bounce test

The old bounce test is still the most widely used test to tell if the shocks or struts are weak. It's not a very scientific test because it requires a certain amount of judgment. Dampers that have obviously lost their guts and allow more than two or three gyrations after rocking the bumper up and down are weak and should probably be replaced.

But what about the "marginal" ones that aren't totally shot but aren't real stiff either? Who's to say if they ought to be replaced?

For this very reason, the Motorist Assurance Program has taken a very conservative approach to the issue of selling replacement shocks and struts. The MAP Uniform Inspection Guidelines say shock and strut replacement should not depend on a vehicle's mileage or whether the dampers failed a bounce test.

The guidelines say replacement is required only if a shock or strut piston rod is bent or damaged, if the shock or strut has broken, has damaged or missing mounting hardware, is binding or seized, is severely corroded to the point where it is weakened (struts only), is missing, or has oil "running down the body."

So what are you supposed to say to a customer if he asks about replacing his shocks or struts? If his car is rocking like a boat every time it hits a bump or comes to a halt, it's obvious that his old dampers have reached the end of the road.

You can therefore recommend new ones to restore "like-new" ride control performance or to improve ride control and handling. But you shouldnít tell a customer he needs new shocks or struts unless his old units require replacing for any of the above defined reasons.

The best way to sell shocks and struts these days is to sell them as ride control upgrade products. You can recommend better shocks or struts to anyone who pulls a trailer, who carries occasional overloads, who wants the utmost in handling performance or who is unhappy with the way their vehicle currently rides.

Problem #2:
Low priority items

According to a recent consumer survey by a leading shock manufacturer, 70 percent of people think the primary function of shocks and struts is to provide a comfortable ride. As a result, shocks and struts are considered a low priority item and tend to be overlooked. Only 21 percent of the people surveyed recognized the fact that new shocks and struts can improve handling and ride control.

On the other hand, the same survey found that the most compelling reason (56 percent) for replacing shocks and struts was to improve vehicle safety, handling and control. The second most often cited reason by consumers (44 percent) was to improve an uncomfortable, bumpy or rough ride.

The safety aspect of ride control usually doesnít receive the emphasis it deserves because few people realize its importance. Yet tests carried out by the Cologne Institute for Traffic Safety in Switzerland found that "marginal" shocks (50 percent less dampening ability than new shocks) increased the straight line stopping distance by 21 feet at 31 mph (a 23 percent increase!). This occurred because the worn shocks allowed the wheels to hop rather than maintain good contact with the road's surface. In other tests, they found that braking while cornering on slick roads with worn shocks could make a vehicle lose control. So there are valid safety reasons too for replacing worn shocks and struts.

Problem #3:
Nobody looks here

Despite the shortcomings of the bounce test, it's still the most common means of finding weak shocks and struts. There are sophisticated electronic units that can measure a damper's ability to control jounce and rebound. But such equipment is beyond the budgets of most shops. So we have to rely on the bounce test as well as our eyes, ears and sometimes the seat of our pants to find ride control problems.

The trouble is, few technicians even take the time to do a simple bounce test unless a customer specifically complains about a ride control problem and asks them to "check out" the shocks and struts. Yet day in and day out, these same technicians never even glance at the shocks or struts on dozens of vehicles that pass through the shop unless theyíre doing a prealignment inspection or other suspension repairs.

It should be standard operating procedure to check the shocks, struts and springs on each and every vehicle that comes your way, regardless of why it's in the shop.

One of the best places to start looking for ride control problems is to interview your customers. When a customer brings in a vehicle, ask him if heís noticed any unusual noises, handing or steering problems lately. If he has, note the symptoms and ask him additional questions about how he uses his vehicle. Does he pull a trailer or haul occasional overloads in the back of his van, pickup or station wagon?

The follow-up to any comments about possible ride control problems, of course, would be a test drive and close visual inspection. A short test drive will tell you more about a vehicle's ride control system than a quick visual inspection or a simple bounce test. How does the vehicle ride on a rough road? How does the steering feel after hitting a bump? Does the body lean when it corners? Does it nose dive when you hit the brakes?

Either before or after your test drive, measure and compare ride height at all four corners. More than half an inch difference side to side may indicate weak springs or another suspension problem. If you want to be really accurate, you should compare the vehicleís measured ride height to the specs in a reference manual. If ride height is at or less than the minimum specified, it's time to recommend new springs.

When the vehicle is raised on a lift, make a visual inspection for obvious problems or damage. Leaky shocks and struts are easy enough to spot, but what about less obvious problems? Shiny spots on suspension stops or between spring coils would be a good clue that the suspension has been bottoming out. Stiffer springs, variable rate springs, air-assist springs and/or stronger shocks would be a good upgrade to recommend here.

The upper bearing plates on the front struts are often overlooked entirely, even when the struts are replaced! Yet they can cause hard steering and noise if worn or badly corroded.

Problem #4
Alignment & tire wear

Misalignment is a major cause of tire wear, but often the underlying cause of the misalignment is weak springs that have sagged with age. When a spring loses height, it changes camber, caster and even toe. Yet many technicians never take the time to check ride height. They focus entirely on readjusting camber, caster and toe back to specs without analyzing what caused the angles to change in the first place.

Springs should be replaced when the vehicleís ride height is at or below the minimum specification listed in a chassis repair manual. Spacers and inserts are sometimes used to temporarily restore ride height, but the better fix is to replace the springs with either standard, heavy-duty or variable rate springs because shimming doesn't restore the original ride quality or spring rate.

Some surveys show that as many as 50 percent of all the cars, light trucks and minivans on the road today could benefit from new springs. Yet 80 percent of these potential sales are being missed because technicians are not measuring ride height often enough, or are merely eyeballing ride height when they should be measuring it.

Tire cupping can be caused by wheel imbalance and/or weak shocks or struts. If the dampers can't keep the tires in firm contact with the road, the tires will hop as they roll and develop a characteristic cupped wear pattern. By the time anybody notices the wear, it's usually too late for new dampers and the tires have to be replaced. That may be good for tire sales, but it's not so good for your customer's pocketbook.

Steering wheel vibrations and shudder after hitting bumps are good clues that the tires are losing contact with the road. It may be the shocks or struts, or it may be worn suspension parts. Either way, the suspension should be checked out to determine the cause.

Problem #5
What are "right" parts?

Standard shocks, heavy-duty shocks or gas shocks (or struts)? Standard replacement springs, heavy-duty springs or variable rate springs? Air springs or air-assist shocks? Helper springs or overload shocks?

When it comes to recommending replacement ride control products, you've got to do your homework. Once you've determined your customer needs new shocks, struts and/or springs, you then have to determine which type of replacement parts best suit his needs. Then you have to explain the various options to your customer and make your recommendation.

Most vehicles can benefit from upgrading to gas shocks and struts. Most late model vehicles have them as original equipment anyway, so why would you want to install anything less? For heavy-duty applications such as utility vehicles, commercial vehicles, or trucks or vans that are used more for their intended purpose than everyday grocery getters, larger, stiffer shocks or struts would be a good choice.

On vehicles that have electronic shocks or struts, you may be confronted with a special kind of problem: the high cost of the replacement parts. Electronic shocks and struts are very expensive and many are not even available as aftermarket parts. One alternative is to replace them with standard dampers that cost considerably less.

As for springs, standard liner rate springs are used as original equipment on most vehicles, but some also have variable rate springs. Standard springs give the softest ride, but may not be the best replacement choice if your customer tows a trailer, hauls extra cargo or has had a problem with bottoming out.

Heavy-duty springs have a higher (stiffer) spring rate than the original springs. They are for applications that require additional load carrying capability, such as station wagons, trucks, vans, RVs or vehicles used for towing. But heavy-duty springs are stiff and increase ride harshness. For this reason, they might not be the best choice for some customers who are "ride sensitive." Many customers would probably prefer a variable rate spring.

Variable rate springs become progressively stiffer the more they're compressed. So under normal use they ride much like a standard spring, but act like a heavy-duty spring when extra load carrying capacity is needed. As a variable rate spring is compressed, the closer spaced coils (which have a lower spring rate) come together shifting the load to the remaining coils which are further apart (and have a stiffer rate). When the load is removed, the closer spaced coils spread out to provide a normal ride.

Regardless of the type of springs, shocks or struts that are chosen, they should always be replaced in pairs to maintain even side-to-side ride control and ride height.

Problem #6
Installation tricks

Most shocks are fairly easy to replace, but some struts can be tricky. On older import vehicles that have cartridge style struts, it's not always necessary to completely remove the struts to replace the cartridges. Most such applications have enough clearance to allow the top of the strut to be swung out from under the fender once the upper mount is unbolted. On some, though, you'll need a special spanner wrench or a pipe wrench to remove the body nut from the strut. On others, you can replace the cartridge from above with the strut in place once the upper bearing plate has been removed.

When installing a new cartridge in a rebuildable strut, about 3 oz. (a shotglass full) of ATF must be poured into the strut housing to aid heat transfer from the cartridge. Also, follow the installation instructions regarding the use of spacers or washers under the body nut on rebuildable struts. Differences in height among replacement cartridges make the use of such spacers necessary.

Replacing the struts usually requires realigning the wheels after the new struts have been installed. You can save yourself some work by marking the position of the camber bolts and upper strut mounts before loosening anything. This helps maintain approximate wheel alignment and should lessen the amount of adjustment that's needed.

If brake lines have to be opened to disconnect them from the struts during strut replacement (cutting the brake line mounting ear can sometimes make this unnecessary), you'll have to bleed the brakes afterwards.

Always follow standard safety precautions when using a spring compressor (verify the correct type of compressor for the application, that the spring is held securely, and that the spring is not overcompressed). And, make sure the spring is properly positioned and seated before the compressor is released.