Hydraulic Control Valve and DCV Repair in the UAE
ASAT repairs and recalibrates hydraulic control valves at our Sharjah workshop. We clean and inspect every spool and bore, lap or hone what is worn, renew all seals, and reset relief valves to the machine manual on our test manifold. The valve goes back with leakage and pressure readings, not just a clean body.
Signs your control valve needs repair
- A cylinder or winch creeps or drifts with the lever in neutral.
- Loss of fine control (feathering) on cranes and excavators.
- Spools that stick or feel heavy, worse with cold oil.
- System pressure lower than spec, or oil running hot.
- Jerky or delayed response from proportional or solenoid valves.
Spool reconditioning, manifold resealing & pressure relief calibration
Directional control valves, proportional valves, and manifold blocks manage hydraulic direction, speed, and overall circuit safety. Worn spools or degraded internal seals cause cylinder drift, jerky movements, or severe pressure drops. ASAT provides thorough cleaning, spool inspection, body resealing, and relief valve pressure calibration to restore fluid control.
- Sectional, monoblock & cartridge valve servicing and rebuilds
- Cracking pressure verification and relief valve bench calibration
- Contamination clearance and complete seal package renewal
Our DCV overhaul process
- 1.Dismantling & Ultrasonic Cleaning: Careful extraction of all spools, poppets, and springs followed by thorough particulate cleaning.
- 2.Bore & Spool Inspection: High-precision inspection for internal wash-out, micro-scoring, binding, or excessive clearance.
- 3.Spool Micro-Polishing: Removing micro-burrs and polishing spools to ensure silky, non-sticking movement inside valve bores.
- 4.Complete Resealing: Replacing all intermediate O-rings, backup rings, wiper caps, and cartridge seals.
- 5.Pressure Setting & Testing: Calibrating main relief valves and port relief settings to design operating parameters.
Valves we repair
- Monoblock and sectional directional control valves
- Proportional and pilot-operated electro-hydraulic valve banks
- Excavator main hydraulic control valve assemblies
- Counterbalance, load-holding & sequence valves
- Custom hydraulic manifold blocks and cartridge valves
How we test and calibrate valves
- Pressure test at working pressure on our valve test manifold.
- Internal leakage measured per section with flow meters on blocked A and B ports.
- Main and port relief valves set and lock wired to the manufacturer's figures.
- Solenoid coil resistance and proportional (PWM) response checked across the range.
Mobile valve service
Before a valve block is removed, our field technicians check pilot pressure, relief settings and coil resistance on site. That confirms the valve is the problem and not the pump or a cylinder.
Turnaround
Control valve repair and calibration: 1 day diagnosis, 2–4 days turnaround, calibrated to OEM pressure settings.
Recent valve repair
A six section proportional valve from a mobile crane came in with winch drift and lost metering control. Varnish had built up in the bores, two spools were scratched, and the main relief spring had set, dropping relief pressure by 40 bar. We honed the bores, lapped the spools, renewed all seals and reset the reliefs, then tested at 280 bar.
Control valve repair FAQs
What is a DCV overhaul?
- A directional control valve overhaul means stripping the valve, inspecting each spool and bore, lapping or honing worn surfaces, replacing all seals and resetting the relief valves, followed by a pressure and leakage test.
Why does my control valve drift in neutral?
- Usually worn or scratched spools, worn check valve seats, or contamination in the bores letting oil pass between ports.
Can you calibrate relief valves?
- Yes. Main and port reliefs are set on our test bench to the figures in your machine manual and lock wired.
Do you repair proportional valves?
- Yes, including coil and PWM checks.
How long does a valve overhaul take?
- Usually 2 to 4 days for a standard DCV.
Can you check a valve on site first?
- Yes. A site check of pilot pressure, relief settings and coils avoids removing a valve that is not at fault.
Start with a quote
Send the machine details. We quote after inspection, before any work starts. Open 24 hours.