Hydraulic System Diagnostics & Field Repair
Mondak Equipment provides hydraulic system diagnostics and mobile field repair for heavy equipment.
When Changing Parts Hasn't Fixed the Problem
Some hydraulic problems are obvious.
Others are the reason Mondak gets called after a pump, valve, hose or other component has already been replaced and the machine still does the same thing.
The equipment may be:
- Slow
- Weak
- Running hot
- Losing performance under load
- Working cold but not hot
- Making unusual hydraulic noise
- Blowing hoses repeatedly
- Damaging pumps or motors
- Operating intermittently
You do not have to know what component is bad before calling.
Tell us what the machine is doing. We'll start there.
Pressure Is Only Part of the Story
A pressure gauge is useful, but pressure alone does not tell you whether a hydraulic system is healthy.
A machine can build pressure and still be slow or weak because it does not have the flow required to do the work.
Depending on the problem, Mondak can look at:
- System pressure
- Hydraulic flow
- Case drain
- Pump output
- Pilot pressure
- Load-sense signals
- Relief settings
- Hydraulic temperature
- Internal leakage
- Suction conditions
- Filter restriction
- Valve operation
- Electronic commands
The test should fit the problem, not the other way around.
Flow & Case-Drain Testing
Flow testing can help determine whether a pump is actually delivering what the machine needs under operating conditions.
Case-drain testing can also help identify excessive internal leakage in certain piston pumps and motors.
These tests are especially useful when equipment:
- Loses performance as it warms up
- Has weak hydrostatic drive
- Builds pressure but moves slowly
- Has suspected pump or motor wear
- Performs differently under load
The goal is to measure what the system is actually doing before expensive components get condemned.
Hydraulic Heat Problems
Hydraulic oil getting hot is a symptom.
The real question is why it is getting hot.
Possible causes include:
- Internal leakage
- Worn pumps or motors
- Relief or bypass flow
- Incorrect pressure settings
- Cooler problems
- Restricted filters
- Suction restrictions
- Incorrect or degraded oil
- Aeration
- Cavitation
- Excessive mechanical load
Installing a larger cooler may lower temperature without fixing the condition creating the heat.
The goal is not simply to make the oil colder. It is to determine whether the system is operating the way it should, and if it isn't, why.
Hydraulic Contamination
A component failure can affect more than the component that failed.
Metal, hose material, dirt, water and other contamination can move through the hydraulic system and damage pumps, motors, valves and other precision components.
Depending on what happened, the repair may also involve:
- Filter inspection or replacement
- Reservoir cleaning
- Hydraulic oil replacement
- Flushing
- Additional filtration
- Cooler and line inspection
- Cleanup after pump or motor failure
A new pump should not become the filter for the old one.
When Hydraulics & Electronics Meet
Modern heavy equipment often combines hydraulics with electronic controls.
A hydraulic function may depend on:
- Joysticks
- Sensors
- Solenoids
- Proportional valves
- Controllers
- Wiring
- Power and grounds
- CAN communication
- Safety interlocks
Sometimes the hydraulic component is capable of doing the work but never receives the correct command.
Mondak works through both sides of the problem instead of assuming every hydraulic symptom is caused by a pump or valve.
Repeated Failures Are Telling You Something
If the same hose keeps blowing, the same pump keeps failing or the same cylinder keeps coming back, another replacement part may only restart the cycle.
Repeated failures can point to:
- Contamination
- Excessive heat
- Pressure problems
- Poor suction conditions
- Incorrect component selection
- Mechanical binding
- Hose routing
- Cooling problems
- Electrical or control issues
If parts have already been changed, tell us.
That history can be some of the most useful diagnostic information we have.
Mobile Hydraulic Field Service
Many hydraulic problems are easier to diagnose on the machine, under load, where the problem actually happens.
Mondak provides mobile hydraulic troubleshooting and repair for equipment that is too large, integrated or inconvenient to bring into the shop.
Field service can include:
- Pressure testing
- Flow testing
- Case-drain testing
- Temperature diagnosis
- Pump and motor troubleshooting
- Valve and manifold troubleshooting
- Hydraulic hose repair
- Leak repair
- Electrical and control troubleshooting
- Component replacement
- On-site repairs where practical
If a pump, motor, cylinder or valve needs teardown, machining or bench repair, the component can come back to the shop while the rest of the machine stays where it belongs.
Stop Guessing at the System
Maybe you already know what failed.
Maybe you have already replaced several things and still do not know.
Either way, give us:
- Equipment manufacturer and model
- What function is affected
- What the machine is doing
- Whether it changes hot versus cold
- Whether the problem is constant or intermittent
- What has already been adjusted or replaced
You do not need to diagnose the machine before calling.
That is what you are calling us for.
Contact Mondak Equipment