Slow, weak or dead. Three different faults.
Hydraulics rarely tell you what is wrong in plain language. The machine just stops doing what it used to do. We test the circuit in order, find which component actually dropped, and fix that one instead of guessing at the most expensive part on the machine.
- Open 24 hours, seven days
- No hourly minimum
- A price before work starts
- Diagnosis on your site
Pressure and flow are not the same problem
Two machines come in with what the operator calls the same complaint, and they need opposite repairs. One will lift an empty bucket fine but stalls the moment there is dirt in it. The other moves at half speed whether it is loaded or not. The first is a pressure problem. The second is a flow problem. Tell those apart at the start and you have already cut the job in half.
Pressure is what lets the machine push. Flow is what makes it move fast. A relief valve set low, a worn pump slipping internally under load, or a cylinder leaking past its piston seal all drop pressure, and the symptom is weakness: fine unloaded, useless working. Low flow shows up as a machine that is simply slow, evenly, all the time, which points at pump output, a restricted line, or a filter nobody has changed in two seasons.
Then there is the third case, where a function does nothing at all. That is usually not a worn part. Something is not getting a signal or a path: a control valve spool stuck, a pilot line blocked, a solenoid with no power reaching it, or a coupler that never fully seated. Dead is often the cheapest of the three to fix, which is worth knowing before anybody talks about a new pump.
This page is about machines that travel: excavators, loaders, tractors, trucks and trailers. Hydraulics that stay bolted to a plant floor behave differently and get a different visit, covered under industrial hydraulic repair.
Useful on the callWhether the machine is weak, slow or completely dead on that function, and whether every function does it or only one. That single answer changes what we load.
What the job runsYou get a figure covering the diagnosis and the trip while we are still on the phone, and short work stays short work on the bill.
Before we arriveLeave the failed part on the machine and note the last thing it did normally. Send us the details.
Working the circuit in order
The fastest way to spend a customer’s money badly is to start at the pump. It is the part everyone suspects, it is expensive, and in most of the systems we open it turns out to be healthy. Fluid flows through a chain of components, and a fault anywhere in that chain shows up at the far end as a weak or slow function. So the chain gets tested in order rather than at the point where the symptom appears.
That means a gauge in the circuit, not a hand on the hose. Pump output pressure gets measured against the machine’s own specification. Relief settings get read, because a relief that has crept down or is dumping early makes a perfect pump look worn out. The control valve gets checked for internal bypass, where fluid takes a shortcut back to tank instead of going to the cylinder. Only after all of that does the cylinder itself get tested for piston seal leakage.
Working that order takes a bit longer on the first hour and saves entire days. A machine that came in as a pump failure has left as a relief valve adjustment more than once. The specification matters here: a reading is only meaningful next to what the manufacturer says the circuit should produce at that temperature and engine speed.
Nobody should pay for a pump because a relief valve was set wrong. Test first, then buy the part the machine actually needs.
Freeman Roadside Repair
Most component failures start as dirt
Call it a pump failure and you describe the funeral, not the cause of death. The great majority of hydraulic components that wear out early were killed by contamination: particles too small to see circulating through clearances measured in fractions of a thousandth of an inch. Every pass, they scrape a little more. The part fails months later and takes the blame.
Grit gets in through open ports during repairs, through a breather cap on a dusty site, past rod seals on a cylinder that has been working in mud, and out of a fluid container that was already dirty. Water counts too, from condensation in a reservoir that heats and cools every day or from pressure washing near a cap. Water in oil kills its ability to carry a load and rusts the parts it is supposed to protect.
Which is why we care what the fluid looks like before deciding anything. Milky oil means water. Dark and varnished means it has been cooked. Gritty or metallic means something upstream is already coming apart, and installing a new component into that system without flushing it is just feeding it the debris that killed the last one. Fluid and filter work is covered under hydraulic fluid service, and it is usually the cheapest hour anyone spends on a machine.
Where the fault usually turns out to be
Once the testing narrows it down, the repair itself falls into a handful of familiar places. Most of them get finished on the same visit.
Pumps and drive motors
Genuinely worn pumps exist, and so do pumps destroyed by a restricted suction line. We look for the cause before fitting a replacement.
Control and relief valves
Spools sticking on varnish or debris, reliefs drifting out of setting, and solenoids that click without moving anything.
Cylinders that drift or leak
A load creeping down on its own, or oil weeping past a rod seal, both of which read as low pressure from the operator’s seat.
Lines, fittings and couplers
A collapsed hose restricts flow without leaking a drop, and a coupler that is not fully home blocks a circuit entirely.
The electrical side of the circuit
On newer machines, hydraulic functions are commanded electrically. A dead function often traces to a switch, a connector or a fuse.
Travel and track problems
When the complaint is that one track pulls or crawls, the fault can sit in the drive motor rather than in the main circuit.
Questions we get about hydraulic faults
Machine parked and not earning? Call any hour and describe it. Photos of the machine and its data plate help.
My machine is slow but everything still works. Is that urgent?
It is worth looking at sooner rather than later. Slowing down usually means something is bypassing internally, and the fluid that takes a shortcut turns into heat. Heat then thins the oil, degrades the seals and accelerates wear on everything else in the circuit. A machine that is merely slow this month is often a machine that is dead next month, and by then the repair list is longer.
Do I need a new pump?
Usually not, though it is the most common thing customers ask for. A weak or slow machine can come from a relief valve out of adjustment, a control valve bypassing, a cylinder leaking past its piston, a restricted filter or low fluid. We test the circuit in order and tell you what the gauge says. If the pump really is finished, you will hear why we concluded that.
Can hydraulic diagnosis actually be done on my job site?
Yes, and it is better done there, because the machine fails under its real load and its real operating temperature rather than idling in a shop. The truck carries gauges, test fittings and fluid, so pressures get read in the circuit while the machine works. Some internal repairs need a bench, and if yours is one, we tell you that on site rather than after the trailer arrives.
What does contamination actually do to a machine?
It wears the internal clearances that make a hydraulic component work. Pumps, valves and motors seal against each other with gaps far smaller than a human hair, and hard particles circulating in the fluid grind those gaps wider on every pass. The part keeps working until it does not. That is why fluid condition and filter history matter more to us than the hour meter does.
One function is dead but the rest are normal. What is that?
That pattern is good news more often than not. When the pump is failing, every function suffers together. A single dead circuit points at something specific to that circuit: a stuck valve spool, a pilot line not delivering its signal, an electrical fault on a solenoid, or an attachment coupler that never fully connected. Those are usually quick fixes once they are found.
How do you charge for diagnostic work?
We give you a figure before we drive out, covering the trip and the time to find the fault, and there is no hourly minimum inflating a short call. If the repair can be done on the spot, you hear what the parts and work add before we start. Nothing beyond finding the fault happens without you agreeing to it first.
Tell us what it stopped doing.
Weak, slow or dead, and on which function. That much over the phone points us at what to bring, and you will know the price and roughly when we arrive before you hang up.
HoursMonday to Sunday, 24 hours
Based inAmerican Canyon, CA
Related workFluid and filters · Equipment repair · Gallery