Hydraulic system maintenance: why it matters and how to troubleshoot with confidence

And the majority of the issues that take the most time and cost the most—the so-called catastrophic hydraulic failures that I've seen—started as something small: a worn hose, dirty fluid, or a loose fitting. These are things that might cost you a little time and money early, but turn into a much bigger problem when they're ignored.

The thing is that these fleets weren’t unlucky; uptime isn't about luck. It's about making sure the small stuff stays small, and you do that by keeping a close eye on the hydraulic system.

FM: What gets overlooked by technicians when working on trucks’ hydraulic systems?

RB: In my experience, the biggest thing guys miss isn't the fluid level; it's the fluid's condition. You can have a reservoir that's full, but if that oil is contaminated or heat-damaged, it's basically liquid sandpaper running through your system.

Another one that gets overlooked is the reservoir breather cap. It's a small part, easy to forget about, but if it's clogged with dirt, your pump can't breathe properly. That leads to cavitation, which sounds a lot like running a blender full of marbles. And that's not something you want to ignore.

Hose routing is another big one. You can replace a hose, but if it's not routed correctly, vibration is going to take over. If you start seeing shiny spots on a hose or nearby metal, that's your warning sign. At that point, it's just a matter of time before it fails.

A zip tie or a protective sleeve might not seem like much, but those small fixes are what keep you out of bigger problems later.

FM: What are some common pain points and quick ways to troubleshoot issues?

RB: If you're looking for the usual suspects, hoses and fittings win every time. They take the most abuse from movement, vibration, and the environment.

After that, it's pump failures, most of which trace back to dirty fluid or running the system low.

When it comes to troubleshooting, I always tell my team to trust their senses before they grab a toolbox.

First, take a beat and listen. A high-pitched whine usually means air is getting into the system. A growl usually means the pump is starving.

Also, carefully feel around. If a valve bank is too hot to touch, you've probably got internal leakage creating heat. [Ed. Note: Hydraulic oil starts to cause damage at around 180 degrees F, and direct contact may inflict third-degree burns on skin. Thermal imaging devices are a safe, non-contact option.]

Then, visually examine the oil. If it looks like a strawberry milkshake, you've got aeration or water in the system.

And don't start by replacing the most expensive component. Start simple. Start at the suction side and work your way through it. Most of the time, the issue is something small, trying to tell you it needs attention.

You just have to be willing to notice it.

FM: What sets successful fleet maintenance teams apart when it comes to managing hydraulic issues?

RB: If there's one thing I've learned over the years, it's that the fleets that stay ahead aren't doing anything complicated. They're just consistent.

They have simple routines that actually get followed. Not a checklist that looks good on paper, but one that technicians use every day without thinking about it.

They train their guys to notice the small things. A hose is starting to rub. A system running a little hotter than usual. A function that feels just a little slower. Those are the things that turn into bigger problems if no one pays attention.

They also keep things clean. Clean fluid, clean fill points, clean work habits. Contamination is behind a lot of the failures we see, and most of the time it's preventable.

And they pay attention to patterns. If the same issue keeps showing up, it's usually telling you something. Good fleets don't just fix it; they figure out why it's happening.

I've seen both sides of it. The fleets that stay ahead of maintenance deal with fewer surprises. The ones that don't usually end up fixing the same problems over and over again.

And in this line of work, it's the surprises that cost you the most.

At the end of the day, whether it's something we see in our own builds at Summit or out in the field, these trucks are built to work as hard as the people using them. Staying ahead of the small stuff is what keeps them that way.