Just recently at 134,000 miles, I replaced the suspension shocks on our Cascadia we call Celeste. Part of the reason for our naming of the truck was the heavenly ride we experienced with our 2022 Cascadia equipped with Hendrickson AIRTEK, Hendrickson OPTIMAAX liftable pusher axle, and Freightliner Airliner rear suspension. This combination, partnered with the LINK CABMATE ROI electronically controlled cab suspension, produced a ride quality that was unbelievably smooth.
Shocks are a funny thing, and probably one of the most overlooked maintenance items on a truck. It's not like one day your shocks go from being good to bad; a suspension shock wears out gradually. And if you’re driving the same truck every day, the degradation of ride quality is so gradual that you typically don’t notice the change.
When you talk to other drivers or maintenance facilitators, you hear a large range of mileages and reasons to replace a shock absorber. Some people use a laser thermometer to check and see if the shock is creating heat, which is an indication that the shock absorber is still functioning properly. To do this, you drive the truck for a period of time, take the infrared thermometer, aim it at the body, and then the dust shield. If they’re at the same temperature, the shock absorber is no longer functioning. So far, I have not been able to get a firm answer on what the temperature spread should be between the body of the shock and the dust cover. Other people, I hear, do not replace the shock until they see a seal going bad, which causes the shock to mist with an oil film.
If a person was to get technical about it, the only real way to truly test a shock's dampening abilities, would be to remove the shock and put it on a shock dynamometer. Of course, we know that there are not any shock dynamometers in any of the shops we frequent unless our shop happens to be a NASCAR, INDY CAR, or Formula One racing team. So, I guess it's safe to say that none of the readers of this blog will be having their truck's shocks tested on a dynamometer anytime soon.
I have found sort of a shade tree approach to having a shock dynamometer built into the truck. For those of you who have read the earlier blogs on our Freightliner Cascadia, Celeste, you will remember that one of the things I noticed was, from the very beginning, my phone, when placed on the edge of my wing panel, never moved. In fact, this held true that my phone just sat there even going through rough construction areas. Of course, after I got moved into my truck, I found a better location to keep my phone. There was another thing that I noticed which was my folder of paperwork for the shipments that I transported would sit on top of my clipboard folder which sits on the floor next to the passenger seat. Over the past last few months, I started to observe that the paperwork would no longer be sitting there when I stopped the truck for a break or the end of my shift.
Celeste, at that point, had 134,000 miles on the odometer. I made the decision to replace the shock absorbers on the steer and tandem axle assemblies. I did not, however, replace the shock absorbers on the CABMATE ROI cab suspension.
As I am writing this blog, I am pleased to say, there was a significant difference in the ride. My paperwork never moved any noticeable amount for the entire week after replacing the shock absorbers. The shocks I used to replace the original units were the OEM part number for the steer axle, liftable pusher axle, and the rear axle received a pair of Sachs Freightliner after-market branded shocks. The reason behind using the OEM part numbers comes from my knowledge of the amount of testing that goes into matching the shock valving characteristics with the suspension spring ring.
It's good to be riding smoothly again. Until next time, everyone be safe and profitable.