Hydraulic Repair Services
Industrial Hydraulic Repair, Testing, Refurbishment & Reliability Services
When hydraulic systems fail, production slows, downtime increases, and replacement costs can quickly escalate. Universal Servo provides comprehensive hydraulic repair, testing, refurbishment, and reliability services for manufacturers throughout Georgia, the Southeast, and across North America.
Our hydraulic division specializes in repairing and testing servo valves, proportional valves, hydraulic pumps, hydraulic motors, cylinders, gearboxes, and complete hydraulic systems. Whether you need emergency repair, preventative maintenance, reliability support, or refurbishment of obsolete equipment, our team has the expertise and equipment to restore performance and minimize downtime.
Hydraulic Components We Service
Universal Servo repairs and refurbishes a wide range of hydraulic components, including:
- Servo Valves
- Proportional Valves
- Hydraulic Pumps
- Hydraulic Motors
- Hydraulic Cylinders
- Hydraulic Power Units
- Gearboxes
- Hydraulic Manifolds
- Pressure & Flow Control Valves
- Directional Valves
- Hydraulic, Pneumatic, & Electrical Actuators
- Pneumatic Valves
Every component is evaluated, tested, repaired, and verified before being returned to service.
Hydraulic Valve Repair Services
Hydraulic valves control the direction, pressure, and flow of hydraulic fluid in a system. They are broadly classified by function into three primary categories—directional control, pressure control, and flow control—with further distinctions by actuation method (manual, solenoid, pilot-operated, etc.), construction (spool, poppet, etc.), and control precision (on/off, proportional, servo).
Even minor valve issues can negatively impact machine performance and reliability.
We repair:
- Proportional Valves
- Servo Valves
- Directional Control Valves
- Pressure Control Valves
- Flow Control Valves
Hydraulic Pump Repair Services
Hydraulic pumps are the heart of any hydraulic system. A failing pump can create loss of flow, pressure loss, overheating, reduced productivity, and costly downtime.
We repair:
- Piston Pumps
- Vane Pumps
- Gear Pumps
- Variable Displacement Pumps
- Fixed Displacement Pumps
Our repair process includes complete inspection, disassembly, cleaning, replacement of worn components, reassembly, and performance testing.
Hydraulic Cylinder Repair
Hydraulic cylinders are critical to lifting, positioning, clamping, pressing, and material handling operations.
Common cylinder repairs include:
- Seal Replacement
- Rod Repair/chroming/replacement
- Barrel Repair/Replacement
- Internal Component Replacement
- Leak Correction
- Performance Testing
Our goal is to restore full functionality while extending service life and reducing replacement costs.
Precision Testing and Reporting with Root Cause of Failure:
Precision testing of hydraulic servo valves, proportional valves, pumps, and cylinders on digital test benches combines high-accuracy sensors, automated control, data acquisition, and software analysis to verify performance against manufacturer specifications or international standards (such as ISO 10770 series for electrically modulated valves, ISO 6404 for servo valves, and ISO 10100 for cylinders). These systems enable repeatable, quantifiable results far beyond traditional manual methods, support automated reporting, and facilitate root-cause analysis of failures through detailed curve interpretation and parameter deviations.
Digital Test Bench Architecture
Universal Servo’s custom digital test benches include:
- A hydraulic power unit (variable-speed pumps with precise pressure/flow control, filtration to maintain cleanliness, and temperature conditioning).
- High-resolution sensors for pressure, flow (including low-range leakage meters), temperature, position/spool feedback (LVDT or similar), and sometimes force/torque.
- Electrical interfaces for both voltage and current command signals (±10 V, ±4-20, 50, 100 mA), and feedback monitoring.
- Data acquisition hardware, and software for automated sequencing, real-time plotting, closed-loop control of test conditions, and data logging.
- Mounting adapters for NG4–NG32 (and larger) valves, pump test fixtures, or cylinder mounting plates.
These benches support both static (steady-state) and dynamic testing under controlled conditions.
Precision Testing Procedures
Servo and Proportional Valves automated tests include:
- No-load flow characteristics — Flow vs. input signal at rated ΔP (curves reveal linearity, symmetry, and max flow).
- Hysteresis, resolution, and threshold — Measure deadband, friction, and minimum resolvable change.
- Pressure gain — Especially near null (critical for closed-loop stiffness).
- Internal leakage / zero-flow leakage — Across the null region and at various signals.
- Null bias/offset and zero setting.
- Step response and frequency response (dynamic performance).
- Spool position feedback (for valves with electrical feedback/LVDT) vs. command.
- Additional checks such as polarity, pressure drop, and endurance/impulse where required.
Digital systems plot curves automatically, calculate parameters (hysteresis percentage, gain slopes), and compare them to limits. Deviations are flagged immediately.
Pumps
Our custom digital pump test bench measures volumetric, mechanical, and overall efficiency across pressure/speed ranges; case-drain leakage; flow vs. pressure curves; temperature rise; vibration/noise; and (in advanced setups) cavitation indicators. Closed-loop control of load and precise speed regulation ensure accurate efficiency mapping and detection of internal wear.
Cylinders:
- All hydraulic cylinders are tested to manufacturer’s specifications, on our hydraulic bench
- Test verify seal integrity and mechanical performance
- Stroke verification and dimensional checks.
- We are equipped to test any servo or proportional controlled cylinders while simultaneously testing the valve, cylinder, and temposonic rod for precise accuracy.
Reporting
Universal Servo generates comprehensive, standardized reports that typically include:
- Identification data (valve/pump/cylinder serial number, model, operator, date/time, oil conditions, cleanliness).
- Numerical results (flow rates, leakage volumes, hysteresis %, gains, response times, efficiencies, friction values).
- Graphical plots (flow vs. signal, hysteresis loops, pressure-gain curves, step/frequency responses, efficiency maps).
- Pass/fail status against programmable limits or OEM/ISO criteria.
- All diagnostics and reporting are uploaded to a QR code attached to every refurbished unit.
Root Cause of Failure Analysis is provided with every repair.
Digital test data enables systematic diagnosis by linking measured deviations to physical mechanisms:
Valves (Servo/Proportional)
- High hysteresis or non-linearity / “ball glitch” → Contamination, spool/sleeve wear, damaged feedback mechanism (feedback wire or ball), or sticky pilot stage.
- Elevated internal leakage near null → Increased spool-to-sleeve clearance from wear or erosion; damaged lands.
- Null shift or bias change → Thermal effects, residual magnetism, contamination buildup, or pilot orifice blockage.
- Slow/poor dynamic response or low pressure gain → Restricted pilot flow, electrical coil degradation, insufficient supply pressure, or mechanical binding.
- Asymmetry or polarity issues → Incorrect assembly, wiring, or first-stage (torque motor/flapper-nozzle) faults.
Curve shapes themselves are diagnostic (flat spots or discontinuities point to specific mechanical problems).
Pumps
- Low volumetric efficiency or rising case drain → Internal leakage from worn pistons, vanes, or ports; clearance increases.
- Reduced flow under load or pressure instability → Wear, cavitation damage, or relief-valve interaction.
- Excessive noise/vibration/temperature → Misalignment, bearing wear, or aeration.
Cylinders
- Internal leakage / drift under load → Worn or damaged piston seals.
- External leakage → Rod seal or gland failure.
- High friction or stick-slip → Seal design issues, contamination scoring, or improper surface finish.
- Stroke or force shortfalls → Mechanical binding, air entrapment, or cushion maladjustment.
Advanced digital systems incorporate anomaly detection, digital twins, or machine-learning models on time-series data to accelerate diagnosis and support prognostics (remaining useful life estimates). Cleanliness monitoring during testing is critical, as contamination is a leading root cause across all components.
Our digital test benches transform subjective “feel” or basic pressure/flow checks into quantifiable, traceable evidence. This supports quality control in manufacturing, reliable post-repair verification, and evidence-based maintenance decisions that minimize downtime and secondary damage in hydraulic systems.
Industries We Serve
Our hydraulic repair services support a wide range of manufacturing and industrial operations.
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Injection Molding & Plastics
Hydraulic systems are commonly used in injection molding machines, robotics, and material handling systems. We help manufacturers reduce downtime and extend equipment life.
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Paper & Forest Products
Paper mills and converting facilities rely heavily on hydraulic systems for material handling, processing, and production equipment. Universal Servo supports facilities throughout the industry.
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Packaging & Converting
Packaging equipment depends on hydraulic power for reliability and production efficiency. We provide repair and support services that keep lines operating.
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Automotive Manufacturing
Automotive suppliers and manufacturers rely on hydraulic systems throughout stamping, forming, assembly, and material handling operations.
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Food & Beverage Manufacturing
Hydraulic systems are widely used in packaging, processing, conveying, and production equipment where reliability is critical.
Looking for a discontinued or obsolete part?
We specialize in helping you find the best solution.
Hydraulic Brands We Service
Our technicians routinely repair and support hydraulic equipment from leading manufacturers, including:
Repair vs. Replacement with Universal Servo: Which Is Right for You?
Repairing hydraulic units is highly cost‑effective and offers quicker turnaround times, minimizing equipment downtime. Buying new units can provide maximum reliability, updated technology for better energy efficiency, and a full manufacturer warranty for long‑term peace of mind.
Key Benefits of Refurbishing
- Budget Friendly: Repairs can cost 50% or less than new, since you are reusing the housing or body and replacing internal components.
- Faster Turnaround: Eliminates the wait time for factory manufacturing or long distance shipping, getting your machinery back up and running faster.
- Root Cause of Failure: Repairing can help identify the cause of failure preventing further problems in the hydraulic system. Our technicians can identify what type of contamination is present. Chrome you have a cylinder going bad, bronze, you have a piston pump problem.
- Time-in-Service Warranty: Warranty starts when you install the unit, not when it is received.
Key Benefits of Buying New
- Enhanced Effectiveness & Performance: New units incorporate the latest technological upgrades, which reduce power consumption, increase precision, and boost overall hydraulic output. May come with Bluetooth options to easily monitor the performance of the unit.
- Recurrent Issues: No wear on hard parts as everything is new. Avoid obsolescence issues with old units.
- Peace of Mind: Comes with a full warranty from the manufacturer. New Atos valves have electronics with a counter inside. This not only allows you to see how long of service you are getting before failures, but Universal Servo uses it to give you a Time-in-Service warranty on new units. Imagine buying new spares — the warranty doesn’t run out before installation.
When to Choose Which
- Choose Repair: If the major structural components (cylinder barrel, pump housing, valve internals) are intact, the cost of repair can be less than 50% of a replacement, and your primary goal is avoiding production downtime.
- Choose Replace: If the unit has experienced catastrophic structural damage (e.g., deep barrel scoring, deep spool cuts), the parts are obsolete, or the component is causing further system damage.
Always Keep a Spare:
Buying new and repairing allows you to get the quickest option and have a spare on the shelf to ensure you don’t experience this downtime again. With Atos vales with Onboard Electronics, you can have Time-in-Service warranties on both units, only offered by Universal Servo.
Hydraulic Testing & Reliability Services
Repair is only part of the process.
Universal Servo provides testing and reliability services designed to verify performance and improve long-term equipment reliability.
Capabilities include:
- Hydraulic Bench Testing
- Pressure & Flow Testing
- Failure Analysis
- Reliability Reporting
- Preventative Maintenance Support
- Root Cause Investigation
Our goal is not simply to repair components but to help manufacturers reduce future failures and improve operational performance.
Our team supports manufacturers across multiple industries with:
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Hydraulic Repair
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Industrial Electronics Repair
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Servo Motor Repair
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Robotics Repair
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Reliability Services
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Engineering Support
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Consulting Services
Frequently Asked Questions About Hydraulic Repair
Most piston, vane, gear, and variable displacement pumps can be repaired and tested.
