Auto Service World
Feature   May 1, 2007   by Jim Anderton

Replacing ‘toilet plunger’ shocks for fun and profit

One of the beauties of writing a "rant," as opposed to a serious automotive aftermarket story is the ability to vent the kind of frustration that we in the aftermarket feel, but can't adequately expre...

One of the beauties of writing a “rant,” as opposed to a serious automotive aftermarket story is the ability to vent the kind of frustration that we in the aftermarket feel, but can’t adequately express, at least to people not in the business. My wife, for example, couldn’t understand why my knuckles had to look like shredded wheat after a job, so I cajoled her into helping me change the clutch in her Civic. It turns out she’s pretty handy. It also turns out that she’ll never repair anything automotive, ever again.

But my point about bleeding over the job was made. As a result of this experience, I was on my own last week when I replaced the shocks on her other beloved machine, a ’05 Silverado 1500 4X4. The vehicle was perfect in her eyes, until a stint at the Bridgestone Racing School made her realize that it’s actually a wallowing pig of a vehicle, largely because of the OEM shock absorbers. At this point I might mention the brand, a major supplier to OEM’s and the aftermarket, but that wouldn’t be fair because it’s the vehicle engineers that specify the ride control.

For the shock manufacturer, the customer is always right. A light truck suspension has been honed over about ninety years into a slightly schizophrenic combination of 21st century high tech and 1800’s Conestoga wagon. Up front, I found beautifully designed control arms and torsion bar springing with a very user friendly bolt-adjusted ride height capability. Bump stops are large and soft, which is good, because the truck uses them often. Shocks are light-truck-easy to replace and serve the dual purpose of damping the spring motion and limiting suspension on the rebound. The OEM shocks are also durable, which is a shame because sensible owners should have their shop replace them with something usable, probably on the drive home from the dealership. I’ve seen toilet plungers that worked better that the shocks on that Silverado.

What were the engineers thinking? I’m guessing three things: Make it cheap, make the ride as car-like as possible, and make it cheap. Cost control is a reality everywhere, but light truck chassis engineers need to get around a huge compromise: performance loaded vs. empty. “Half-ton” pickups now have GVWR’s and towing capacities that used to be seen in one-ton trucks, with rear suspensions that are correspondingly beefy. They’re also buckboard primitive, with leaf springs still the technology of choice. Flat springs work, but how do you build in progressive rate with a simple leaf stack?

Apparently, you can’t, at least not well and between the railroad boxcar spring stack and interleaf friction, the rear shocks appear to be there mainly to have something to wipe off when you’re off roading. Fortunately, they’re as easy to replace as the fronts, except for the dirt falling into your eyes. I replaced all four with a top-line aftermarket set from another major manufacturer, who shall remain nameless, and the improvement was remarkable. Better ride and less sway, a win-win that the dullest motorist could appreciate. Why won’t I name the manufacturer of those excellent shocks? Because one box contained the wrong hardware kit, resulting in much swearing and some improvisation from yours truly. I don’t want to imply that they screw up all the time, but they’ll hear from me! Can you sell replacement ride control for pickups with perfectly good OEM shocks? I’m a believer and my wife is so happy with the truck’s handling, now I get to install a rear sway bar. I only hope I get to drive the truck someday.

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