You hit a pothole and the impact not only fills your ears, but resonates all the way to your spine. There's no denying it: Your car's suspension needs some work.

There are various suspension set-ups from MacPherson struts and double wishbones to single shock absorbers and multilink structures. Leaf springs are found on some pickup trucks and older large vehicles, but not on today's new models.

Here, we'll take a look at a MacPherson suspension structure, which consist of a hydraulic cartridge, a coil spring, assembled as one.

Photo: Marie-Andrée Ayotte

You can buy a MacPherson strut from any car dealer or parts retailer, which also means they are available in a wide price range. Personally, I don't like used suspension components because you never know how long they'll last. A repairman once offered me a “deal:” only $400 to rebuild the entire suspension with used parts. Two months later, one of the cartridges broke down and was leaking oil.

You don't have to use the same OEM components, either: Aftermarket suspensions are another way to go. You'll find Monroe products at Canadian Tire, but make sure to visit your local parts retailer for a wider selection of brands and models.

KYB sells expensive, high-quality struts with a lifetime warranty, while Prime Choice has much cheaper stuff. Even recyclers can sell you affordable, ''good as new'' suspension parts.

For an average compact car, a single cartridge costs $60-$100, while a complete package with all the necessary components (including a preloaded spring) will set you back $200-$300.

Once you've found the right set-up
Replacing a preassembled MacPherson strut is extremely simple when rust doesn't get in the way. You simply have to locate the nuts from under the hood (or inside the trunk, depending on the model), as well as a bolt that connects the strut to the tie rod. Then you'll want to take out the faulty strut and install the new one. It's that simple.

If you decide to replace only the cartridge, you'll need a special tool called a spring compressor. First, remove the upper strut-mount nuts and bolts, but leave the centre strut shaft nut in place or disaster will follow (the compressed spring will shoot like a rocket). Using the spring compressor, compress the spring to take pressure off the upper strut mount. Then, loosen the shaft nut to remove the upper strut mount. Finally, replace the cartridge and repeat these steps in reverse order.

If you have any doubts, leave it to your favourite mechanic to replace the strut for you. It will likely prove more expensive, but then again, peace of mind is priceless. A savvy grease monkey knows quite a few tricks and will charge you an hour or two depending on the number of cartridges that need to be replaced.

As far as I'm concerned, I like spending an afternoon in the garage, getting my hands dirty and cursing the sky for rusted bolts. How about you?