Shocks and struts are the bits of your car that keep you from scraping the the bottom of your car on the road but also make it so you don't feel every little bump. Shocks and struts affect the control and handling characteristics of your vehicle while keeping your tires to the road. They control the action of the spring to resist bottoming out -- like when you hit a pothole -- and keep the movement of the springs under control when they rebound. Without shocks and struts, your vehicle would continually bounce and bound down the road. While it looks fun in rally video, experiencing it going to work is a real bummer.

Since winter is the time of frost heaves and infinite potholes, it's a good idea to check that shocks and struts are in top condition during the winter months.

cracked winter road

How They Work

Shocks provide resistance by forcing hydraulic fluid (oil) through valves in the piston as it moves up and down. Because the oil cannot be compressed, only a certain amount of fluid can be forced through these valves, which creates resistance to the vehicle movement. It's like a liquid spring that doesn't really lose springiness over time.

How to Tell if Shocks and Struts Need Replacement

Shocks and struts will wear out gradually. It's normal. If you think about what they have to do (absorb tons of little impacts and push back to keep your car from being too bouncy), it makes sense. Honestly, it's kind of surprising how long it takes. Outside of regular driving, there are a lot of things that affect how much wear is actually happening and how fast it's happening.

We're in Maine. Do you drive an hour to work on well-maintained highway or do you drive for half an hour on dirt roads? That makes a difference. It's winter. Are the potholes so bad that they had to be patched, or are they annoying but something that's being put off until frost heaves are done? Or do you drive on a road like last winter's where the pothole was so bad it had to be patched, but every four days another frost heave left the pothole as big as ever?

tire close up

How much ice or salt or sand or gravel has been on the roads that your tires have been kicking up under the vehicle? It's not just pothole plinko, all kinds of stuff can make life harder for shocks and struts. Pistons rod can easily be nicked or damaged by flying gravel allowing grit and dirt to damage the piston seal.

Among signs of worn shocks or struts:

  • Do you experience excessive bounce (three or more bounces) when crossing an intersection?
  • When stopping quickly does your vehicle rock back and forth? 
  • While applying your brakes firmly at higher speeds, does your vehicle drift left or right?
  • When changing lanes quickly does your vehicle rock or sway from side to side?

A lot of stuff affects handling, but bringing your vehicle in to be checked by one of our Subaru Certified Technicians if you think there might be an issue is a good way to get ahead of any issues before they become dangerous and before they cost more money.

Categories: Service, Parts
Tags: advice