Independent repair of Abex jet-pipe servovalves: 447400-series, 34 Series, and 35 Series — used in aerospace and FM-labeled industrial systems. The Abex hydraulic line is now part of Parker, and many 447400-series valves carry Parker Jet-Pipe Servovalve labels today. Backed by a long-running donor parts pool built from decades of repairs. Working on this kind of hardware since 1975.
Nameplate decode: part numbers like 447400-1002 with a 312A6077P0045 suffix tell us the specific configuration. The label often also shows pressure rating, flow rating, and any FM marking. Send the full string when you call.
The 447400 family is the Abex servovalve we see most often. Jet-pipe pilot stage, FM marking on the label, and now in the Parker catalog as a "Parker Jet-Pipe Servovalve". A representative unit: 447400-1002 with the 312A6077P0045 suffix.
On the bench, the 447400 gets the same jet-pipe work as any servovalve in this category: pilot-stage clean, jet alignment, spool service, coil rebuild, and seal kit, with a final pressurized test under documented procedures.
Abex jet-pipe servovalves are close-tolerance hydraulic hardware used in demanding industrial and aerospace systems. The shop evaluates each unit, finds what failed, and rebuilds the valve at the component level using parts on hand or pulled off donor units when needed.
N210 / Pilot
Jet-pipe pilot stage
Jet-pipe nozzle cleaning, jet alignment, contamination removal from the pilot path, and trim against documented procedures on 447400-series and related Abex bodies.
N220 / Hydraulics
Spool, body, and seals
Spool service, contamination scoring repair, seal replacement, and internal-leakage verification on 34 Series, 35 Series, and 447400-series valves.
N230 / Electrical
Coil and electrical
Pilot stage coil rebuild, connector and cable repair, and feedback wire work on units with feedback loops.
We are a small repair shop, not an Abex distributor. The series below are simply the ones that come through often enough to be familiar. If your part number is not on this list, send it anyway. We work on what we can.
Fig. 03
447400 series
Jet-pipe servovalves with FM markings on some nameplates. Examples: 447400-1002 / 312A6077P0045 rated at 10 GPM, 1000 PSID, 3000 PSI max.
Fig. 04
34 Series
Abex 34-series servovalves. Discontinued and current units kept in service with donor parts pulled from inventory.
Fig. 05
35 Series
Abex 35-series servovalves. Older lines often kept on legacy industrial and aerospace equipment past OEM support.
N350 On the shelf
Abex units in stock right now
Live inventory — rebuilt and as-is Abex hardware currently on the shelf. Stock moves; if a listing matches your part number, call before it ships to someone else.
Abex Products We Service
74 models available
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A description of the symptom helps the diagnosis, but a part number is often enough. The categories here cover the kinds of trouble that come in across Abex jet-pipe servovalves.
Fault log — typical intake
Jet-pipe pilot
Jet nozzle plugging, jet misalignment after contamination event, pilot-pressure null shift, or feedback wire wear at the pilot.
Spool and body
Spool wear, contamination scoring, sticky spool action, internal leakage past the spool, or seal failure on the 447400, 34, and 35 series bodies.
Coil and electrical
Burned coils, open windings, damaged connectors, or cable strain at the entry point on units in service for decades.
Physical condition
Heat damage, contamination evidence, corroded connectors, damaged housing, or evidence of prior repair attempts on legacy Abex hardware.
Most Abex jobs follow the same four blocks. 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.
N510
Get in touch
Phone or email with the Abex part number, a quick note on the symptom, and a photo of the nameplate if it helps.
N520
Bench review
Once the unit arrives, a tech evaluates it, checks the jet-pipe pilot and spool, and runs it on the hydraulic stand to confirm what failed.
N530
Cost & approval
We call back with the cost and a rough turnaround. Repair work starts only after your sign-off.
N540
Repair, test, ship
Failed components are replaced from inventory or off donors, the valve is verified under pressure, and the unit ships back.
Fig. 06 — hydraulic bench, Westland facility
N600 Bench verification
Each unit gets pressurized before ship
Repaired Abex jet-pipe servovalves are checked on the hydraulic test stands before they leave. Flow, pressure gain, response, and null are verified against documented procedures for the family.
6.1Flow characterization across the operating range for the 447400, 34, and 35 series.
6.2Pressure gain and step-response measurement against documented procedures.
6.3Internal and external leakage checked after seal and spool work.
NC Servo has a long-running donor parts pool built from past valve and drive jobs, including Abex and Parker jet-pipe hardware. Stock changes constantly, so call about the exact part number. Sometimes a rebuilt match is on the shelf; other times the repair depends on donor components for older 447400, 34, and 35 series families the OEM no longer stocks.
7.1Aftermarket and donor parts for jet-pipe Abex units.
7.2If we have a rebuilt match for your part number, trade in your old valve for a discount on the rebuilt.
7.3No match on the shelf? We can suggest a comparable Abex, Parker, or cross-brand option, or repair the unit you have.
7.4Rebuilt valves carry the same 1-year warranty as a fresh repair.
NC Servo works on the servovalve hardware: the body, spool, jet-pipe pilot stage, coils, and any onboard electronics. Hydraulic system design, fluid selection, approval documentation, and getting the valve back on the machine stay with your team or your installer.
OUTSystem pressure setup and hydraulic schematic decisions remain on your side.
OUTCertification. Repairs are hardware-level work, not approvals — suitability for return to service and any certification that applies stay solely with the customer, OEM, or qualified authority.
OUTPutting the valve back on the machine follows your normal startup process.
N800 More on Abex repair
Related pages and brands
Abex jet-pipe servovalves often share a machine or a system with other close-tolerance hydraulic hardware. The pages below cover related coverage and other servovalve brands.
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 Abex or Parker Hannifin?
No. NC Servo Technology is an independent, third-party repair facility and is not affiliated with, authorized by, or endorsed by Abex, Parker Hannifin, or any related entities. All Abex and Parker trademarks are the property of their respective owners.
Which Abex servovalve models do you cover?
Jet-pipe servovalves in the 447400 series (including units like 447400-1002 / 312A6077P0045 rated for 10 GPM at 1000 PSID) and the 34 Series and 35 Series families. Send the part number off the nameplate and we will tell you what we have.
Do you work on Abex servovalves with FM markings?
Yes. Some 447400-series valves arrive with FM markings on the original label. NC Servo repairs the valve hardware at the component level. The repair is not a certification: we do not provide, renew, or represent FM, FAA, or any other approval, and suitability for return to service rests solely with the customer, OEM, or qualified authority.
Is Abex still its own company?
No. Abex's hydraulic servovalve line is now under Parker Hannifin, and many 447400-series units are listed in the Parker catalog as Parker Jet-Pipe Servovalves. We service hardware labeled Abex, Pneumo Abex, and Parker.
How long does an Abex 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. 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 Abex 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 Abex, Parker, or cross-brand alternative.
What is the warranty on an Abex 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.
N990 Get a quote
Abex servovalve down?
Give us a call with the 447400-series part number, a photo of the nameplate, or a quick description of the symptom. 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.
