How to Troubleshoot Slow Hydraulic Cycle Times
Have you noticed your truck or trailer hydraulics have seemed slow lately? You hit the control, and wait for movement. And wait. And wait some more.
This could be due to an issue with the cylinder or actuator causing cycle time to drag out longer than it should. If you want your equipment to move at its normal speed again, you'll need to pinpoint what the issue is and fix it. To help you with this, Higgs Parts has put together this guide on how to troubleshoot slow hydraulic cycle times.
What Is Cycle Time?
Cycle time is the time a hydraulic cylinder or actuator takes to complete one full movement from start to finish.
On a truck or trailer hydraulic setup, the cycle starts when you activate the control and ends when the cylinder or actuator reaches the end of its travel. The system relies on oil flow, pressure, valves, hoses, and moving parts all working together to create that motion.
Flow affects speed. Pressure affects force. When either one falls out of range, cycle time can increase.
How To Tell If Cycle Time Is Slow
Slow cycle time means the same movement takes longer than it did before under the same working conditions. A normal cycle time should stay fairly consistent when the load, engine speed, oil temperature, and travel distance stay the same.
A cycle that takes about 25% longer than normal shows a measurable loss of speed. For example, if a function normally takes 20 seconds and now takes 25 seconds under the same conditions, the system is no longer moving oil through the circuit at its normal rate. If it takes 30 seconds, the slowdown is past minor and needs attention before the equipment keeps working under load.
You’ll get the most accurate reading when you measure cycle time the same way each time. Start the timer when you activate the control, then stop it when the movement reaches full travel. Writing down the number lets you see whether the cycle gets faster, slower, or stays the same after each check.
Common Causes of Slow Cycle Times
Slow cycle times usually come from lost flow, lost pressure, restricted oil movement, or resistance in the equipment. Once you know the system is slower than normal, these are the most common areas to check.
Low Oil Supply
The pump has to draw hydraulic oil from the reservoir before it can send oil to the cylinder. If the reservoir level drops, the pump can’t deliver the same amount of oil through the circuit.
That lower oil supply slows the cylinder during the stroke. The movement can turn uneven because the pump keeps working without a full, steady feed from the tank.
Air In the Hydraulic Fluid
Hydraulic oil transfers force to the cylinder because it stays dense under pressure. Air compresses instead, so it uses up pressure before the cylinder gets the force it needs.
Air in the fluid can make the actuator feel delayed or soft. Under load, the cylinder may pause until pressure builds enough to keep the stroke moving.
Contaminated Fluid
Hydraulic systems use tight clearances inside valves, pumps, and cylinders. Contaminated fluid carries grit through those spaces and can slow how quickly parts respond.
As dirty fluid keeps circulating, it wears seals and internal surfaces. Over time, the system loses efficiency, and the same movement takes longer than it used to.
Hose Flow Restriction
Oil has to pass through the hose at the right volume for the cylinder to move at normal speed. A damaged inner liner can narrow that path even when the hose cover looks fine.
Once the inside of the hose pinches the flow, the cylinder gets less oil during each second of operation. The pump may still run, but the actuator can’t move at the proper pace.
Clogged Filter
A filter protects the hydraulic system by catching debris in the fluid. After it fills with debris, it turns into a restriction and slows oil movement.
Restricted flow at the filter can limit how much oil reaches the pump or how quickly oil returns to the tank. The actuator then moves slower because the system can’t circulate oil at the needed rate.
Worn Pump Parts
The pump creates the flow that moves the cylinder. Worn internal parts let oil slip past instead of forcing it through the system.
When this happens, the pump can spin without moving enough oil per minute. The cylinder may still move, but each cycle takes longer because the pump isn’t keeping up with demand.
Low Relief Valve Setting
The relief valve sends oil back to the tank when system pressure reaches its set limit. If that limit is too low, oil leaves the pressure side before the cylinder gets enough force.
This reduces available pressure during the stroke. The cylinder may keep moving under lighter work, then slow down when the load demands more force.
Internal Cylinder Bypass
Piston seals keep oil on the correct side of the piston inside the cylinder. When those seals wear, oil can slip past the piston instead of driving the rod forward.
The cylinder loses pushing force even without an outside leak. Under load, it may move slowly, creep through the stroke, or fail to hold position.
Bound Linkage or Mounting Hardware
The cylinder can only move as freely as the parts connected to it. If a pivot, pin, bracket, or mount binds, the hydraulic system has to push against extra resistance.
That resistance slows the stroke even when oil flow and pressure are normal. When the hydraulic side tests correctly, the connected hardware needs a close look.
Getting The System Back to Normal
If it's taking your cylinder or actuator a long time to complete a full cycle, use this guide on how to troubleshoot slow hydraulic cycle times to help narrow down the issue and get your truck or trailer back to work.
If you determine you need replacement parts for your hydraulic system, or a new cylinder or actuator entirely, get them at Higgs Parts. We sell hydraulic and pneumatic original parts for big rigs like semi-trucks. With quality products from trusted brands, affordable prices, and dependable service, getting your equipment back to work doesn’t have to be complicated.