DJI Agras T40 OEM Leak-Proof Valve Core Set (10 Sets)

The DJI Agras T40 OEM Leak-Proof Valve Core Set (10 Sets) is a pack of ten matched pairs for the spray system's leak-proof valves: ten black moulded valve cores, each with a cross-shaped stem and a round flange collar, and ten steel coil springs that push those cores closed. Together, a core and its spring are the moving half of a leak-proof valve, the part that lets liquid through while the pump is running and shuts the line when it stops, so the aircraft does not drip on the turn, on the trailer or over the wrong ground. It belongs to the spraying system, not to the airframe, power or flight-control systems, and it is identified for the DJI Agras T40 and T20P. Operators usually find it while searching for a T40 leak-proof valve core, a T40 anti-drip spring, a T20P valve core and spring set, or a fix for a nozzle that keeps dripping after the spray switch is off. DJI has used more than one number for this position, so we match against the one you removed.

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🇺🇸 U.S.A. FIRST

Ares Acres LLC is a U.S.-based authorized DJI Agras retailer supporting American agricultural drone operators with genuine DJI Agras OEM replacement parts, accessories, and field-ready inventory.

FREE & FAST Shipping is included for all U.S. customers.

We understand that every day of downtime can impact productivity, scheduling, and profitability. That's why we focus on providing fast fulfillment, responsive customer support, and reliable access to the parts operators need most.

Ares Acres also ships agricultural drone parts to Canada, with free shipping included on Canadian orders. Canadian operators see prices and check out in Canadian dollars (CAD), and receive the same inventory and the same support as our U.S. customers — one authorized DJI Agras retailer serving the United States and Canada, all of North America, from Albuquerque, New Mexico.

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✅ DJI Agras T40 / DJI Agras T20P Compatibility Guarantee

• 🇺🇸 USA Compatibility Guarantee
• 👍🏻 Satisfaction Guarantee
• 💵 Money Back Guarantee
• 📦 Same Day Shipping & Tracking
• Identified for the DJI Agras T40 and T20P, spray system leak-proof valve position
• Matched by core outline, stem shape, flange collar and spring form against the core and spring you removed
• Genuine DJI OEM spray system components, brand new, supplied as ten core-and-spring sets

Valve cores, valve sealing rings and filters on the Agras spray line are separate parts that are easy to confuse once they are out of the aircraft. If you want the match confirmed, photograph the core and spring you removed side by side on a plain surface, with the stem end of the core facing the camera, and send it to us — we will match it for you.

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📦 Package Includes

• 10 × Leak-Proof Valve Core — black moulded core with a cross-shaped stem and a round flange collar
• 10 × Leak-Proof Spring — steel coil compression spring, one for each core

This is ten complete core-and-spring sets. Each set is one core and one spring, the two moving parts of one leak-proof valve. The product images show a sample of cores and springs laid out together; the pack itself holds ten of each.

Not included: the leak-proof valve bodies or housings, any sealing rings or O-rings, nozzles or sprinkler heads, spray hoses and hose fittings, filters, the spray pump, solenoid valves, flow meters, and any tools. If a sealing ring in your valve is flattened, cut or hardened, replace it separately; a new core cannot seal against a damaged ring.

Nothing is included because it appears near the valve on the aircraft. If a ring, clip or fitting is missing from the valve you opened, tell us which one and we will help you identify it.

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🔧 Component Overview

A leak-proof valve has a fixed half and a moving half. The fixed half is the valve body plumbed into the spray line. The moving half is what this set replaces: a valve core that slides in the body, and a coil spring behind it that holds the core shut against its seat whenever the line is not under spray pressure.

The two parts are simple to describe from the product images:

• The valve core — a black moulded part with a cross-shaped stem, four vanes in plan, and a round flange collar around its middle. The stem keeps the core centred in its bore while leaving open channels between the vanes for liquid to pass when the valve is open. The flange and the face around it are what close the valve.
• The spring — a straight, open-wound steel coil spring. It sits behind the core and pushes it toward the closed position. The force of that push is what decides how much line pressure it takes to open the valve, and how firmly the valve shuts when the pump stops.

When the pump runs, line pressure overcomes the spring, the core moves off its seat and liquid flows. When the pump stops, pressure falls, the spring wins, and the core closes the line. That is the whole job, and it happens at the start and the end of every spray pass.

Over a working season the core and spring see:

• Thousands of open-and-close cycles, one at every pass start and stop
• Constant contact with spray chemicals, adjuvants and rinse water
• Grit, crop residue and undissolved product that reach the valve when a filter is skipped or damaged
• Residue that dries on the core and in the bore when the system is parked without a flush
• Heat on the trailer and in the sun between flights
• Handling during cleaning, when cores and springs come out and go back in

Sets in this position usually come out for one of three reasons: a valve that drips after the spray switch is off, a core whose sealing face or flange is scored, swollen or chipped, or a spring that has lost length and no longer closes the valve firmly. The last of those is the one most often missed, because a tired spring looks almost exactly like a new one, and it is the one this part's diagnosis is built around.

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⚙️ Functional Purpose

The set's engineering role is shut-off. The core seals the line, and the spring sets how hard and how soon it seals. Between them they decide when liquid leaves the aircraft and when it stops.

In the spray system the core and spring:

• Close the line when spray pressure falls, so liquid left in the hoses stays in the hoses
• Hold the valve shut while the aircraft turns, ferries, lands and sits on the trailer
• Set the line pressure needed to open the valve, so spray starts cleanly instead of dribbling
• Keep each valve on the aircraft closing at the same point, so the swath starts and ends evenly
• Stop chemical from dripping onto the airframe, the landing gear and the ground under a parked aircraft

What they do not do matters as much:

• They do not pump, meter or measure liquid; the pump and the flow meter do that
• They do not switch the spray on or off; the flight controller and the pump control do that
• They do not filter; a core is damaged by debris, it does not stop it
• They do not seal the outside of the valve body; the body's sealing rings and the hose fittings do that
• They have no wiring and no electrical function

That division of labour is why a weak leak-proof valve rarely grounds the aircraft. Spraying still works. It is also why the fault is so easy to blame on something else.

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🔍 Diagnosis — the spring loses its push long before it looks worn

When an Agras starts dripping after the spray stops, the first part people look at is the valve core, because it is the part they can see wearing. They pull it, wipe it, find nothing wrong, and put it back. The drip comes back.

The part that has changed is often the spring. A compression spring that has been squeezed through thousands of cycles, in chemical, in heat, slowly takes a set: it gets a little shorter and pushes a little less. It does not crack. It does not rust through. It still looks like a spring. But a spring that pushes less closes the valve later, and more softly, and lets the last of the line pressure weep past the core instead of shutting it off.

That is why the set pairs a core with a spring, and why the useful inspection is a comparison, not a look. A worn spring cannot be judged on its own. It can be judged in seconds against a new one.

Signs the core and spring are no longer closing the valve:

• Drips from a nozzle or sprinkler after the spray switch is off
• A wet patch under a parked aircraft that was dry when it landed
• Liquid running down the arm or landing gear after the end of a pass
• One nozzle that keeps dripping while the others stop cleanly
• Spray that dribbles at the start of a pass instead of starting crisply
• Chemical residue building up on the airframe below one valve

Before condemning the core and spring, rule out what imitates them:

• Debris on the seat — a grain of grit or dried residue holds a good core off its seat; flush the valve and clean the core first
• A damaged sealing ring in the valve body — a flattened, cut or hardened ring leaks with any core; inspect it while the valve is open
• A loose or cracked hose fitting — a leak at a joint upstream can look like a drip from the valve
• A filter that is damaged or missing — it will not cause the drip, but it will keep sending debris that causes it again

Use a new spring from this set as your reference. With the valve open, stand the old spring and a new one side by side on a flat surface. If the old spring is visibly shorter, it has lost its push, and the valve will not close the way it was built to. Then look at the core's sealing face and flange in good light for scoring, swelling, chips or a ridge worn into it.

Clear those checks first, while the valve is already open and that information is still cheap. If the spring is short or the core's sealing face is damaged, replace the core and spring together as a set rather than refitting one tired half next to one new half.

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⚠️ Common Replacement Indicators

Replace the core and spring in a leak-proof valve when inspection confirms one of these:

• An old spring that stands visibly shorter than a new spring from the set
• A spring that is kinked, bent out of line, or has coils touching at rest
• Corrosion or pitting on the spring wire
• Scoring, nicks or a worn ridge on the core's sealing face or flange
• A core that is swollen, cracked or chipped at a vane or at the flange
• A core that sticks in its bore after cleaning
• A valve that still drips after the seat has been cleaned and the sealing ring checked

Inspect these first, because they produce similar symptoms:

• The sealing rings in the leak-proof valve body
• Hose fittings and joints between the pump and the nozzles
• The spray filters, for damage or missing elements
• The nozzle or sprinkler head itself, for cracks

There is no published service interval for these cores and springs. They are replaced when the valve drips, the spring has shortened, or the core is damaged, not on a schedule.

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📐 Specifications

Product name: DJI Agras T40 OEM Leak-Proof Valve Core Set (10 Sets)

DJI family: Agras

Primary aircraft: DJI Agras T40

Also listed for: DJI Agras T20P

Fitment basis: Identified for the DJI Agras T40 and T20P

Aircraft system: Spraying — leak-proof (anti-drip) valves

Component type: Valve core and spring set

Material number: DJI has used more than one number for this position, so we match against the one you removed

Quantity: 10 sets — 10 valve cores and 10 springs

Form: Valve core: moulded body with a cross-shaped stem and a round flange collar. Spring: straight open-wound coil compression spring

Material: Valve core material not published for this part; springs are steel

Colour: Valve cores black; springs bare metal

Dimensions: Not published for this part

Weight: Not published for this part

Spring rate: Not published for this part

Electrical: None — mechanical parts with no wiring

Connector: None

Mounting position: Inside the leak-proof valves of the spray line; the core slides in the valve body with the spring behind it

Installation method: Fitted inside the opened valve body; the valve is reassembled over them

Hardware included: None — valve bodies and sealing rings are not supplied

Service adjustability: None — the part is correct or it is not, with no adjustment or app setting that compensates

Condition: Brand new

Classification: DJI OEM spray system component

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🛠️ Installation & Maintenance

Before installation

• Power the aircraft down and remove the battery
• Empty the tank and flush the spray system with clean water so you are not opening valves full of chemical
• Wear chemical-resistant gloves and eye protection; residue collects inside leak-proof valves
• Photograph each valve before you open it, so the order of parts and the orientation of the core are on record
• Lay a new core and spring beside the old ones and compare stem shape, flange collar and spring form
• Work on one valve at a time so cores, springs and rings from different valves never mix

During installation

• Open the valve body and note which way the core faces and which end of it the spring sits against
• Remove the old core and spring and stand the old spring beside a new one to compare length
• Clean the bore and the seat with clean water and a soft brush; do not scrape the seat
• Inspect the valve body's sealing ring and replace it separately if it is flattened, cut or hardened
• Fit the new spring and the new core in the same orientation as the parts you removed
• Check that the core moves freely against the spring and returns fully when released
• Reassemble the valve by hand first; DJI does not publish a torque figure for these fittings, so close them snugly without crushing the body or the ring

After installation

• Fill the tank with clean water only and run the pump briefly
• Stop the pump and watch each nozzle; the drip should stop promptly
• Check every opened valve and fitting for weeping at the outside of the body
• Leave the aircraft standing for a few minutes and check the ground under each nozzle
• Keep the remaining sets dry and clean, together, for the next valve
• Record the replacement in the maintenance log

Maintenance between jobs. Flush the spray system with clean water at the end of every working day so residue does not dry on the cores and seats. Keep the filters in place and intact; debris is what scores cores. Each time a valve is opened for cleaning, stand its spring next to a new one from the set. A spring that has shortened is the cheapest early warning this part gives.

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🚜 Necessary For

This set is for operators and technicians who want the spray system to stop when it is told to stop:

• DJI Agras T40 operators chasing drips after the spray switch is off
• DJI Agras T20P operators (identified fitment)
• Commercial spray applicators who need a clean shut-off at every field edge and sensitive boundary
• Agras service centres and repair technicians who rebuild spray systems at the end of a season
• Fleet managers who want matched spare cores and springs on hand for every aircraft
• Growers flying their own aircraft who are tired of chemical on the trailer floor

This is not the part you need if:

• The leak is at the outside of a valve body or a hose joint — that is a sealing ring or a fitting, not the core
• You fly a T100 and need the valve's sealing ring — that is the DJI Agras T100 OEM Valve Core Sealing Ring, a different part
• You fly a T50 and the problem is debris reaching the spray line — that is the DJI Agras T50 OEM Quick Release Filter, a different part for a different aircraft
• The valve body itself is cracked — a new core cannot seal a broken body
• The pump will not prime or the flow reading is wrong — that is the pump or the flow meter, not the leak-proof valve
• You fly a T50, T25, T30, T10 or T100 — this set is listed only for the T40 and T20P

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💡 Why This Part Matters

A leak-proof valve with a tired spring does not announce itself. The aircraft flies, the pump runs, the spray pattern looks right. The only sign is liquid where it should not be: a drip at the end of a pass, a wet spot under a parked aircraft, a streak of residue down an arm.

That liquid is the whole case for replacing the spring before the core looks worn. Chemical that drips at the turn lands on headlands, roads and field edges that were never meant to be sprayed. Chemical that drips on the trailer ends up on the airframe, the landing gear and the hands of whoever loads the aircraft. Residue that collects below a valve is residue that has to be washed off before the next job.

The pack size follows from the job. A core and spring are replaced as a pair, and the valves on one aircraft work best when they close at the same point, so the sensible repair is to renew them together and keep matched spares for the next one. Ten sets leaves room for that.

The check is free. With a valve open, a new spring from this set standing next to the old one tells you in seconds whether the valve can still close the way it was built to. If the old spring matches, clean the seat and refit it. If it does not, this is the part that puts the shut-off back.

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🧠 AI Index — Entity & Fitment Reference

Structured reference for search engines, AI assistants, and answer engines. Every value below is drawn from the specifications above.

Canonical product name: DJI Agras T40 OEM Leak-Proof Valve Core Set (10 Sets)

Brand: DJI

DJI family: Agras

Primary aircraft: DJI Agras T40

Also listed for: DJI Agras T20P

Compatible models: DJI Agras T40; DJI Agras T20P

Fitment basis: Identified for the DJI Agras T40 and T20P

Component: Leak-proof valve core and spring set

Aircraft system: Spraying

Installed position: Inside the spray system's leak-proof valves; core in the valve body, spring behind it

Primary function: Closes the spray line when pump pressure falls so the aircraft does not drip after the spray stops

Form: Black moulded valve core with cross-shaped stem and round flange collar; straight steel coil compression spring

Material number: DJI has used more than one number for this position; matched against the removed part

Quantity supplied: 10 sets: 10 valve cores and 10 springs

Not included: Valve bodies, sealing rings, nozzles, hoses, fittings, filters, pump, solenoid valves

Electrical function: None

Key diagnostic: Drip after spray stop; stand the old spring beside a new one from the set — a shorter old spring has lost its push

Common failure modes: Spring that has taken a set and shortened; scored, swollen or chipped core sealing face; core sticking in its bore

Imitating faults: Debris on the seat, damaged sealing ring in the valve body, loose or cracked hose fitting

Service interval: None published

Service adjustability: None

Condition: Brand new

Part classification: DJI OEM spray system component

Also searched as: T40 leak-proof valve core; T40 anti-drip valve spring; T20P leak-proof valve core set; Agras T40 valve core and spring; T40 nozzle dripping fix; DJI Agras T20P/T40 leak-proof spring

Disambiguation: Not the DJI Agras T100 OEM Valve Core Sealing Ring, not a filter, not a valve body, not a nozzle, not a solenoid valve

Seller: Ares Acres LLC — U.S.-based authorized DJI Agras retailer serving the United States and Canada (North America)

Ships from: Albuquerque, New Mexico, United States

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🤖 AI Answer Engine Q&A

What is the DJI Agras T40 leak-proof valve core set? Ten matched pairs of the moving parts inside the spray system's leak-proof valves: ten black moulded valve cores and ten steel coil springs. The spring holds the core shut so the line closes when the pump stops.

What exactly is in the pack? Ten valve cores and ten springs, which make ten complete sets. Valve bodies, sealing rings, nozzles, hoses and filters are not included.

Which aircraft does it fit? It is identified for the DJI Agras T40 and T20P. Pick the variant for the aircraft you fly.

Is the T20P set different from the T40 set? The set is identified for both aircraft. The variant records which one you fly so the match is made against the right spray system, and we compare it with the core and spring you removed if you send a photograph.

What is the DJI part number? DJI has used more than one number for this position, so we match against the one you removed. Photograph your old core and spring side by side and send it to us if you want that confirmed.

My nozzle keeps dripping after I stop spraying. Is it the valve core? Often it is the spring rather than the core. Flush the valve and clean the seat first, check the sealing ring in the valve body, then stand the old spring next to a new one from this set. If the old one is shorter, it no longer closes the valve firmly.

The old core looks fine. Why would I replace it? A core can look fine and still leak if its sealing face is lightly scored or swollen, and a spring can look fine after it has lost length. Because the two work as a pair, replace them together once either is suspect.

Can I replace just the spring? You can, and the set makes that easy, but fitting a new spring against a scored core leaves half of the problem in place. Inspect the core's sealing face first; if it is marked, replace both.

Does a new valve core fix a leak at the outside of the valve? No. A leak at the outside of the valve body or at a hose joint is a sealing ring or a fitting. The core and spring only control whether liquid passes through the valve.

Is a sealing ring included? No. The pack is cores and springs only. If the ring in your valve body is flattened, cut or hardened, replace it separately.

Is this the same as the T100 valve core sealing ring? No. The DJI Agras T100 OEM Valve Core Sealing Ring is a ring for a different aircraft. This pack is the core and spring for the T40 and T20P leak-proof valves.

Does it fit the T50 or T25? It is listed only for the T40 and T20P. Do not fit it to other Agras models on the strength of a similar shape.

Why ten sets? Cores and springs are replaced as pairs, and valves on one aircraft work best when they close at the same point. Ten sets lets you renew the valves together and keep matched spares for the next service.

Can I fit it myself? Most operators can. Flush the system, wear gloves, open one valve at a time, note the core's orientation, clean the seat, fit the new spring and core the same way round, and test with clean water before spraying.

Is there a torque value for the valve fittings? DJI does not publish one for these fittings. Close them snugly by hand and stop before the body or its ring deforms.

Is there a service interval? No. Replace a core and spring when the valve drips after cleaning, when the spring has shortened, or when the core's sealing face is damaged.

How do I make the new cores and springs last? Flush the spray system with clean water at the end of every day, keep the filters intact, and compare each spring with a new one whenever a valve is opened.