Servo and amplifier valves
Oilgear servo valves and servo amplifier valves used in closed-loop control. Pilot stage cleaning, spool service, coil rebuild, seal replacement, and bench testing.
NC Servo Technology - Westland, Michigan
734-326-6666
Independent Repair Shop. Not Oilgear.
Third-Party Repair of Oilgear Hydraulic Valves
Independent third-party repair of Oilgear (Oil-Gear) servo valves, proportional valves, servo amplifier valves, and directional, pressure, and flow control valves. Heavy-industrial heritage on machines in marine, energy, oil and gas, defense, and steel applications. Backed by a 19,000+ unit in-house inventory we pull aftermarket and donor parts from. NC Servo is not affiliated with Oilgear. Working on this kind of hardware since 1975.
Heavy industrial heritage
Oilgear valves off marine, energy, oil and gas, defense, and steel hydraulics.
Servo + proportional + amplifier
Servo valves, proportional bodies, and servo amplifier valves all on the same bench.
One-year warranty
Standard on parts and workmanship for Oilgear repairs and rebuilt units.
Where Oilgear Valves Live
Five heavy-industrial markets Oilgear shipped into
Oilgear is more common on heavy industrial hydraulics than on standard machine-tool work. The five markets below are the ones we see the hardware come off of most often. The repair work is the same; the application context helps us identify the variant.
Industrial
Heavy hydraulic press, forming, and metal-shaping lines.
Mobile
Off-highway and mobile equipment hydraulic control.
Oil & gas
Wellhead, pipeline, and offshore platform hydraulics.
Defense
Marine, ground vehicle, and defense-system hydraulic control.
Energy
Power generation, steam and gas turbine governor controls.
Service Coverage
What NC Servo does with an Oilgear valve
Oilgear's catalog covers servo, proportional, and amplifier valves alongside directional, pressure, and flow control bodies. The shop opens each unit, finds what failed, and rebuilds it at the component level using parts from inventory or pulled off donor units.
Proportional and directional
Proportional directional valves and standard directional control valves. Coil work, spool service, driver-card checks where present, and full functional verification.
Pressure and flow control
Pressure control valves and flow control valves on heavy-industrial Oilgear systems. Body internals, poppet seats, and seal kits.
Oilgear Coverage
Oilgear part numbers through the door
We are a small repair shop, not an Oilgear distributor. The categories below are simply what comes through often enough to be familiar. If your part number is not in this list, send it anyway. We work on what we can.
Servo and servo amplifier valves
Closed-loop hydraulic control bodies. Pilot stage and coil rebuild on units across the Oilgear servo line.
Proportional and directional
Proportional directional control valves and standard directional control bodies on heavy-industrial hydraulics.
Discontinued and obsolete
Older Oilgear lines the OEM no longer services. Donor parts pulled from the in-house pool keep these in service.
Common Faults
What usually shows up on an Oilgear repair
A description of the symptom helps the diagnosis, but a part number is often enough. The categories below cover the kinds of trouble that come in across Oilgear servo, proportional, and directional valves.
| Pilot stage | Pilot-pressure null shift, contamination in the pilot path, flapper damage, or feedback wire wear on Oilgear servo valves. |
|---|---|
| Spool and body | Spool wear, contamination scoring, sticky spool action, internal leakage past the spool, or seal failure on directional and flow control bodies. |
| Coils and amplifier | Burned coils, open windings, failed servo amplifier output stages, or signal-conditioning drift on units with onboard electronics. |
| Heavy-industrial wear | Heat damage, contamination evidence from oil-and-gas service, corroded connectors from marine environments, and seal hardening on long-running heavy-industrial units. |
Repair Path
From part number to ship-back
Most Oilgear jobs follow the same four steps. Lead time varies because some repairs need parts pulled off a donor unit, so we only commit to timing once a tech has the valve on the bench.
Get in touch
Phone or email with the Oilgear part number, what machine it came off, and a quick note on the symptom.
Bench review
Once the unit arrives, a tech opens it, inspects the spool and pilot stage, and runs it on the hydraulic stand to confirm what failed.
Cost & approval
We call back with the cost and a rough turnaround. Nothing happens without your sign-off.
Repair, test, ship
Failed components are replaced from inventory or off donors, the valve is verified under pressure, and the unit ships back.
Bench Verification
Each Oilgear valve gets pressurized before ship
Repaired Oilgear valves are checked on the hydraulic test stands before they leave. Flow, pressure gain, response, null, and leakage are verified against documented procedures for the family.
- Flow characterization across the operating range for the Oilgear body.
- Pressure gain and step-response measurement against documented procedures.
- Internal and external leakage checked after seal and spool work.
- Older stands kept on hand for legacy Oilgear hardware that predates current test fixtures.
Inventory & Parts Pool
A 19,000+ unit pool with Oilgear hardware in it
NC Servo's in-house inventory holds over 19,000 valves and drives accumulated since 1975, including Oilgear servo, proportional, and directional bodies. That pool is where the shop pulls aftermarket parts and donor components for older Oilgear units that the OEM no longer stocks.
- Aftermarket and donor parts for Oilgear servo, proportional, and amplifier valves.
- If we have a rebuilt match for your part number, trade in your old valve for a discount on the rebuilt.
- No match on the shelf? We can suggest a comparable Oilgear or cross-brand option, or repair yours.
- Rebuilt valves carry the same 1-year warranty as a fresh repair.
Repair Scope
Where the line is on an Oilgear repair
NC Servo works on the valve hardware itself: the body, spool, pilot stage, coils, and any onboard amplifier electronics. Hydraulic system design, fluid selection, and getting the valve back on the machine stay with your team or your installer. We do not repair Oilgear hydraulic pumps.
- Internal valve work: spool service, seal replacement, pilot stage cleaning, coil rebuild.
- Servo amplifier electronics: component-level board repair where the model has integrated electronics.
- System pressure setup, schematic decisions, and pump-side work remain on your side.
- Putting the valve back on the machine follows your normal startup process.
More on Oilgear Repair
Related pages and brands
Oilgear hardware often shares a heavy-industrial system with valves from related brands. The pages below cover related coverage and adjacent valve work.
Valve repair hub
The full range of servo and proportional valve repair NC Servo handles, across the brands that come through the shop.
Industrial valve repair
How heavy-industrial hydraulic valve work fits into the broader shop services.
Vickers servo valves
Another American hydraulic-valve brand the shop services. Useful when Oilgear and Vickers hardware sit on the same press or hydraulic system.
Repair vs replace
When component-level repair makes sense versus buying new or rebuilt.
Oilgear valve down?
Give us a call with the Oilgear or Oil-Gear part number, a photo of the nameplate, or a quick description of the machine it came off. We will check the shelf, and if we have a rebuilt match you can swap your old one for a discount. If we do not, we can suggest a comparable valve or repair the one you have.
FAQ
Common questions about Oilgear repair
A few things customers ask before sending a unit in. Anything not covered, give us a call at 734-326-6666.
Is NC Servo affiliated with Oilgear?
No. NC Servo Technology is an independent, third-party repair facility and is not affiliated with, authorized by, or endorsed by Oilgear or any related entities. All Oilgear and Oil-Gear trademarks are the property of their respective owners.
Which Oilgear products are in scope?
Oilgear servo valves, proportional valves, servo amplifier valves, directional control valves, pressure control valves, and flow control valves. We do not repair Oilgear hydraulic pumps.
Do you work on discontinued Oilgear valves?
Yes. A lot of Oilgear hardware in service today is on heavy industrial, marine, and energy systems that have outlasted the original supplier relationship. We rebuild discontinued Oilgear servo and proportional valves with parts from inventory or pulled off donor units.
Can NC Servo recover programs from a failed Oilgear valve?
Most failures are hardware, and the unit comes back working with its program intact. Corrupted programs are rare; if one is already corrupted before the unit reaches us, that's the one thing we can't recover.
How long does an Oilgear repair take?
It varies. NC Servo is a small independent shop, and lead time depends on the valve, what is wrong with it, and whether parts have to come off a donor unit. Give us a call once the unit ships in, and we can give a current estimate after a tech has looked at it.
What if the Oilgear valve is beyond economic repair?
If the valve is not fixable, we will let you know and help source a replacement: a rebuilt match if we have one on the shelf, or a comparable Oilgear or cross-brand alternative.
What is the warranty on an Oilgear repair?
One year on parts and workmanship for repairs and rebuilt units. Standard exclusions apply for contamination, improper installation, and out-of-spec operation. Flushing and filtering the hydraulic system before reinstalling a repaired valve is recommended.