Keep a close eye on worn-out suspension bits
March 28 2018, Brian Turner - Driving.ca - Sprint Marketing
Modern suspension systems hide wear symptoms well – almost too well, to the point where it's too late
If your wallet hasn’t thanked your vehicle yet, maybe it should. One single system on today’s vehicles that shows the most improvement in reliability over years past has to be the lowly suspension system. For vehicles from only a few decades back, having shocks and springs replaced was almost seen as routine maintenance. But thanks to less weight, improved design and engineering, and production of modern shocks, springs and struts – along with multi-link setups – almost have lifetime reliability. Almost.
From the driver’s point of view, the problem with most suspension designs is that they can mask symptoms from weakened struts to the point that they can damage other components before it’s too late. Most of this is due to their tendency to suffer from very gradual degradation often caused by fluid or pressurized gas loss. And because they are often assembled together with springs in traditional MacPherson strut or coilover shock layouts, it’s hard to accurately determine their condition from a jounce test. This is where you simply apply all your weight to each corner of a vehicle, then suddenly release it and count the number of rebounds it takes for the suspension to stop moving. This rebound factor is crucial, and it should take less than three on a functional unit, because it helps maintain solid tire contact with the road over varying surfaces.
So, if you can’t test them in the driveway and nothing feels wrong on the road, how do you check them? You can look for signs of any fluid leaking around the shiny metal piston of each unit. This can be difficult with the wheels or fender liners in place. It also won’t work if the struts or shocks are gas-charged rather than hydraulic-liquid filled. It’s much easier to ask for this quick inspection when your chariot is in for routine oil service or other maintenance needs. Few shops charge much. if anything for this report for regular clients.
Your ears can give you much more indication of certain suspension problems than anything else. Control arms, ball joints, multi-link arms and rods, and their related rubber or synthetic bushings will usually start to clunk, squeak, squawk, and rattle over bumps when they develop excessive wear. Of course it’s much easier to hear a noise rather than see one, and in many cases, these units have to be inspected for any excessive free-play or stiffness in their motion range to determine the correct course of action.
If your ride is exhibiting a rubbery squeak or squawk noise, one DIY fix is to try it to spray any bushings in the affected corner with a shot of WD40 or similar treatment one at a time and then either road-test the auto or jounce test it to see if the problem disappeared.