Stanadyne DB2, DB4 & DB 310 Diesel Injection Pump Rebuild Service
The Stanadyne DB2, and its successor the DB4, are among the most widely used rotary diesel injection pumps ever built, and Valley Fuel Injection has been rebuilding both the right way for decades. It is a mechanical, opposed-plunger distributor pump found on light trucks, tractors, generators, and industrial equipment from the 1970s through the 2000s. When a DB2, DB4, or DB 310 wears out, a proper rebuild is almost always faster, cheaper, and better than chasing down a new pump that may no longer be made. We rebuild your own core and calibrate it to factory specification, so you get a pump matched to your engine instead of a generic replacement or an imported knockoff.
The Valley Fuel Injection Difference
We are a rare breed. There are not many shops left in the country with the training, the certification, and the test equipment to rebuild a diesel injection pump to factory standard, and fewer still that do it at our level. This is not a cheap imported knockoff and it is not a throw-together seal-kit job. It is a genuine, certified, factory-spec rebuild, done by hand and proven on the bench before it ever leaves the building.
When you send a pump to Valley Fuel Injection, it is rebuilt by licensed, factory-certified diesel technicians, to the same standard the pump held the day it left the factory, and it is backed by a real warranty. That is the whole point of what we do.
Applications We Rebuild
The DB2, DB4, and DB 310 family covers hundreds of engine and equipment combinations. The most common we see:
| Engine / Equipment | Typical Applications |
|---|---|
| GM 6.2L & 6.5L | 1982-1993 Chevrolet/GMC pickups, Suburbans, vans, and military HMMWV/CUCV (mechanical 6.5) |
| Ford 6.9L & 7.3L IDI | 1983-1994 F-250/F-350 and E-Series with the International 6.9 and 7.3 non-turbo/IDI diesels |
| John Deere | 300-series, 4019/4219/4239, 4045 and 6068 tractors, combines, and industrial engines |
| Perkins & CAT | Perkins 4-cylinder industrial engines and Caterpillar-badged equivalents (1004 and similar) |
| Marine & Industrial | Gensets, irrigation pumps, forklifts, and marine auxiliaries running Stanadyne rotary diesels |
Common DB2, DB4, and DB 310 Models We Rebuild
The DB2 and DB4 family spans hundreds of part numbers. These are some of the specific Stanadyne models that regularly come across our bench, most on John Deere and Perkins agricultural and industrial engines:
DB2435 series: DB2435-4451, DB2435-4546, DB2435-4759, DB2435-4972, DB2435-5011, DB2435-5142
DB2635 series: DB2635-4482, DB2635-5082
DB4 series: DB4327, DB4429, DB4627, DB4629 and related variants
DB 310 series: the earlier single-cylinder DB pump, still common on older John Deere and Perkins equipment
Do not see your exact number? It does not matter. We rebuild every DB2 and DB4 variant Stanadyne ever built. Read the model number off the tag on your pump, call 530-668-0818, and we will confirm it and quote your rebuild.
Any product image shown is a representative example. Your DB2 or DB4 pump may differ in appearance by application, year, and configuration. We rebuild your exact pump to its factory specification.
Signs Your DB2, DB4, or DB 310 Needs a Rebuild
- Hard starting, no-start, or long cranking when the engine is cold or hot
- Loss of power, sluggish throttle response, or a noticeable drop in top speed
- Hunting, surging, or an idle that will not settle down
- Diesel fuel leaking from the pump housing, the throttle shaft, or the top cover
- Excessive smoke, rough running, or a knock that changes with fuel delivery
- Fuel in the governor housing or a pump that has ingested water or contaminated fuel
How We Rebuild Your DB2, DB4, or DB 310
A Valley Fuel Injection rebuild is not a seal kit and a coat of paint. Every pump is torn completely down and built back to factory standard, one measured part at a time:
- Complete teardown and inspection. We disassemble the entire pump and inspect every single component against Stanadyne factory wear limits. Nothing is reused on assumption.
- Deep cleaning. Every part is ultrasonically and thoroughly cleaned so we are building on bare, spotless metal, not old varnish and debris.
- Factory-certified replacement parts. Transfer pump blades and liner, cam ring, roller shoes, drive components, delivery valves, and a complete overhaul gasket and seal kit. We replace what needs replacing with genuine factory-certified components, never cheap generic substitutes.
- Hydraulic head, governor, and advance service. The head and rotor, governor, and automatic timing advance are serviced and set so fuel delivery is even across every cylinder.
- Calibration and testing on real machines. The finished pump is mounted on a professional, computer-controlled Stanadyne test bench and calibrated to your pump’s exact factory specification sheet. We set transfer pressure, timing advance, and fuel delivery at every point on the governor curve and prove it before it ships.
That final step is what separates a real rebuild from a parts swap. Anyone can bolt in a seal kit. Very few shops can put your pump on a bench, calibrate it to spec, and stand behind the result.
Our Warranty
We control every step of the rebuild, so we stand behind it. Every pump and injector we rebuild carries a 1-year warranty. Electrical and electronic components are warrantied for 30 days. A healthy lift pump and clean, water-free fuel are essential to pump life, so we recommend fresh fuel filters at installation to protect your rebuild.
What a DB2, DB4, or DB 310 Rebuild Costs
Typical Rebuild Cost
$1,250 to $1,850 typical range
Most Stanadyne DB2, DB4, and DB 310 rebuilds land between $1,250 and $1,850, with a typical rebuild around $1,450. These are real figures from our recent Stanadyne rebuilds, not markup guesses. Pumps with heavier wear, or that need a new hydraulic head, run higher. Because every rebuild is priced on your pump’s actual condition, we give you a firm quote after inspection, before any work begins.
Prices above cover the service and parts. Any applicable sales tax, plus shipping and small shop fees (such as a hazardous-waste disposal fee), are added at invoicing, so your quote reflects the full out-the-door number before any work begins. Buying tax-exempt? Qualifying diesel repair shops, fleets, farms, and agricultural operations can purchase tax-free. Set up tax-exempt purchasing by submitting your resale or exemption certificate once, and every qualifying order is tax-free going forward.
How It Works · Call for Pricing and Availability
Because every Stanadyne rebuild is done on your own core, pricing depends on the pump’s condition and the parts it needs, so we quote each job individually. Here is the process:
- Call us with the number on your pump so we can confirm whether it is a DB2, DB4, or DB 310 and talk through your symptoms.
- Ship the pump to us or drop it off. We tear it down, inspect it, and give you a firm quote before any work begins.
- We rebuild and bench-calibrate the pump, then return it ready to install, backed by our warranty.
Call 530-668-0818 for pricing and turnaround, or start your rebuild online → and we will walk you through shipping it in.
Why Valley Fuel Injection
Valley Fuel Injection & Turbo is a full-service, factory-certified diesel fuel injection shop in Woodland, California, serving truck owners, farmers, fleets, and other repair shops across the country. We are a Bosch-authorized service center with the tooling, the test equipment, and the certification to rebuild rotary pumps correctly, and we have been doing it long enough to have seen just about every DB2 failure there is. When a shop cannot fix it, they send it to us. Ship your pump from anywhere or visit us at our Woodland shop.
Want the full technical rundown on the DB2 and DB4 before you send yours in? Read our in-depth Stanadyne DB2 and DB4 injection pump rebuild guide.
Frequently Asked Questions
How much does a Stanadyne DB2, DB4, or DB 310 rebuild cost?
Most Stanadyne DB2 rebuilds run between $1,250 and $1,850, with a typical rebuild around $1,450. Pumps with heavier wear, or that need a new hydraulic head, can run higher. Pricing depends on the condition of your pump and the parts it needs, so we give you a firm quote after inspection, before any work begins. Call 530-668-0818 for current pricing.
Do I send you my pump, or do you have one in stock?
This is a rebuild service for your own core. You ship us your pump or bring it in, we rebuild and recalibrate it, and we send it back matched to your engine. Rebuilding your core is usually faster and less expensive than sourcing a new pump, and many DB2 pumps are no longer manufactured.
How long does a rebuild take?
Turnaround depends on our current shop schedule and parts availability for your specific pump. We give you an honest timeline when we quote the job. If you are down and need a fast turnaround, tell us when you call and we will do our best to prioritize it.
What warranty comes with the rebuild?
Every pump and injector we rebuild carries a 1-year warranty. Electrical and electronic components are warrantied for 30 days. We control every step of the rebuild in-house, from teardown to final bench calibration, which is why we can stand behind it. A healthy lift pump and clean, water-free fuel are essential to pump longevity, so we recommend fresh fuel filters at installation to protect your rebuild.
What makes a Valley Fuel Injection rebuild different from a cheap replacement pump?
We are one of the few certified shops left that rebuilds these pumps to true factory standard. Every part is inspected against factory wear limits, deep-cleaned, and replaced as needed with factory-certified components, then the finished pump is calibrated to exact spec on a computer-controlled Stanadyne test bench and proven before it ships. That is a different thing entirely from a cheap imported knockoff or a throw-together seal-kit job, and it is backed by our 1-year warranty.
My pump number is not on your list. Can you still rebuild it?
Almost certainly. The DB2 was fitted to far more equipment than we can list here. If the pump carries a Stanadyne DB2 tag, we can rebuild it. Call 530-668-0818 with the number stamped on the pump and we will confirm.
Can I ship my pump to you from out of state?
Yes. We rebuild pumps for customers nationwide. Remove the pump, pack it securely, and ship it to us. We inspect it, quote the rebuild, and return it ready to install.
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