Kubota 1J808-53052 Fuel Injector Assembly | Genuine Common Rail Injector for V2403-CR and D1803-CR

Kubota part number 1J808-53052 is the genuine fuel injector assembly (Kubota catalog description INJECTOR,ASSY) for the V2403-CR-TIE4 and D1803-CR-TIE4 Tier 4 common rail engine families. It is a Bosch-built common rail injector, Bosch number 0445110775, and it is the current part in the factory supersession chain that began with 1J808-53050 and 1J808-53051. If your parts book or an old invoice shows either earlier number, this is the correct up-to-date replacement.

Valley Fuel Injection & Turbo in Woodland, CA has specialized in diesel injection since 1993 and is an authorized Kubota dealer. We supply genuine Kubota engine parts, and because we run a full common rail repair shop in-house, we can also help you confirm an injector really is the problem before you spend the money.

Application & Fitment

Confirmed engine applications:

• Kubota V2403-CR-TIE4 Tier 4 common rail diesel engines
• Kubota D1803-CR-TIE4 Tier 4 common rail diesel engines
• Production years approximately 2017 through 2021

Known equipment applications include the Kubota R430 and R430CA compact wheel loaders. Through its CAT cross reference 477-7735, this injector also serves CAT-branded machines powered by these Kubota engines. Specific CAT model coverage varies, so we verify every order by engine serial number before it ships.

Watch the part number carefully. The similar 1J801-53052 injector (Bosch 0445110777) fits the V2403-CR-EF03 engines used in Kubota L-series and MX tractors, and it is a different, non-interchangeable injector. One digit is the only difference between the two Kubota numbers. If there is any doubt, call us with your engine model and serial number and we will confirm the correct injector before you order.

Cross-Reference Part Numbers

• Bosch: 0445110775 (0 445 110 775)
• CAT: 477-7735 injector assembly (CAT 477-7984 is also referenced against this injector)
• Kubota: 1J808-53050 and 1J808-53051, earlier numbers superseded by 1J808-53052

Frequently Asked Questions

Does 1J808-53052 replace 1J808-53050 and 1J808-53051?

Yes. Kubota superseded 1J808-53050 to 1J808-53051 and then to the current 1J808-53052. If your engine originally shipped with either earlier number, this injector is the correct factory replacement.

Is 1J808-53052 the same as 1J801-53052?

No. Despite the nearly identical numbers, 1J808-53052 is Bosch 0445110775 and appears on the R430 loader family and CAT-crossed applications, while 1J801-53052 is Bosch 0445110777 and is used on the V2403-CR-EF03 engines in Kubota L-series and MX tractors. They are not interchangeable, which is exactly why we ask for your engine serial number before shipping.

Is this a genuine Kubota injector?

Yes. Valley Fuel Injection is an authorized Kubota dealer, and this listing is for the genuine Kubota injector assembly, built by Bosch for Kubota’s Tier 4 common rail program. It is the same injector a Kubota dealer would install, not a will-fit copy.

Why do I see this common rail injector cheaper online?
Short answer: it is usually not the same part — and common rail does not forgive “close enough.” Read why ↓

Search any OE number and eBay, Amazon and a dozen storefronts will show it well under dealer cost, sold by outfits with no name, no address and no phone number. We lose business to those listings every week — and we see a lot of them come back through our shop. Here is what is actually different.

• The part number proves nothing on its own. Counterfeit injectors and pumps are stamped with the same OE numbers as the real thing, in housings cast to look identical. The number in the listing title tells you what the seller claims it is, not what came off an OE line.
• “Remanufactured” is not a regulated word. A genuine reman unit is stripped to bare components, has its wear parts replaced — nozzle, plunger and barrel, solenoid, seals — and is then run on a calibration bench until it meets the original flow and response spec. A cheap one is very often cleaned, resealed, painted and shipped. Both get called remanufactured.
• No full teardown, so no idea what is worn. A proper rebuild means the unit comes apart completely and every part gets inspected and measured against spec — not just the ones that are obviously bad. Skip the teardown and you are reusing worn internals inside a freshly painted housing. It will run on the truck. It will not last.
• No factory-spec bench load testing. A unit is not finished until it has been run under load on a test bench and made its numbers across the range, not just at one easy point. That bench time is most of what you are paying for. Sellers working on price cut it first, because nobody can see it in a photo.
• The warranty has to be honored by someone. Everything we remanufacture in house carries a one-year warranty, with 30 days on electrical components. Parts we supply as an authorized dealer carry the manufacturer’s own warranty. Either way you call us, a real shop in California, and we sort it out. A marketplace warranty usually means shipping the part overseas at your own cost and hoping for a reply.
• No core program. We credit your rebuildable core back in full. Discount sellers generally will not take one, so the gap narrows the moment you account for the core you are now stuck holding.
• Common rail has no tolerance for “close enough.” These injectors meter fuel in fractions of a millisecond at pressures north of 20,000 psi, across multiple events per stroke. A nozzle or control valve that is merely near spec will not throw a code on the bench at idle — it shows up as a cylinder that runs hot, a balance rate that drifts, fuel in the oil, or a rail pressure fault six months out. And the labor to go back in is the same as it was the first time.

We are an authorized dealer and a working fuel-injection shop — we have been rebuilding and testing this hardware in Woodland since 1993, and the people who answer the phone are the people who run the benches. Not sure this is the right part for your engine? Call us with your serial number before you order and we will confirm it. Send your rebuildable core back and the core charge is refunded. And if a price somewhere else looks too good, call 530-668-0818 and we will tell you straight whether it is a deal or a problem.

Why Buy From Valley Fuel Injection?

• Authorized Kubota dealer. Genuine OEM parts through the official Kubota channel, not gray-market stock.
• Diesel injection specialists since 1993. We test and repair pumps and injectors every day through our diesel fuel injection services shop, so you are talking to people who actually work on these systems.
• Serial-number fitment verification on every common rail order, which matters in a part family with look-alike numbers.
• Straight answers by phone. Call and you reach a technician-led parts counter in Woodland, California, not a call center.

Pricing & Availability

Call 530-668-0818 for current pricing and availability on the 1J808-53052 injector, or reach us through our contact page. Please have your engine model and engine serial number ready so we can verify fitment and quote the right injector the first time. Replacing a full set? Let us know how many you need when you call.