The Caterpillar 3304 and 3306 are some of the most durable industrial diesels CAT ever built, and the fuel injection pumps that feed them are exactly the kind of work Valley Fuel Injection has specialized in for decades. Whether your engine runs the earlier sleeve-metering fuel system or the later New Scroll version, we rebuild the pump you have. When one of these pumps finally wears out, a proper CAT 3306 injection pump rebuild, or the same service on a 3304, is almost always faster, cheaper, and better than chasing a replacement pump for an engine this old.

These engines routinely outlast the machines they were bolted into. We rebuild your own core and calibrate it to Caterpillar specification on the bench, so you get a pump matched to your engine instead of a generic replacement or an imported knockoff.

Applications We Rebuild

The 3304 and 3306 went into a huge range of Caterpillar machines and stationary installations. The most common we see:

Common 3304 and 3306 Injection Pumps We Rebuild

Caterpillar used two distinct fuel systems across the 3300 series over its long production run, and we rebuild both versions to factory specification:

3304 / 3306 sleeve-metering: Earlier 3300-series industrial, track, and genset engines
3304 / 3306 New Scroll: Later New Scroll fuel system engines

Not sure which fuel system your engine has? It does not matter. We rebuild every 3304 and 3306 injection pump Caterpillar fitted, sleeve-metering and New Scroll alike. Call 530-668-0818 with what you know about the engine and the machine it is in, and we will identify the pump and quote your rebuild.

Signs Your 3304 or 3306 Pump Needs a Rebuild

• Hard starting or long cranking, hot or cold
• Low power under load, a dozer or loader that cannot pull the way it used to
• Surging at governed speed, especially under genset or irrigation load
• Black smoke under load or at rated speed
• External fuel leaks from the pump housing or fittings
• Governor instability, an idle or rated speed that will not hold steady
• Poor running or poor throttle response after the engine has ingested water or contaminated fuel

How We Rebuild Your 3304 or 3306 Pump

A Valley Fuel Injection rebuild is not a gasket kit and a coat of paint. Every 3300-series pump is torn completely down and built back to Caterpillar standard, one measured part at a time:

• Complete teardown and inspection. We disassemble the entire pump and governor and inspect every single component against Caterpillar factory wear limits. Nothing is reused on assumption.
• Deep cleaning. Every part is thoroughly cleaned so we are building on bare, spotless metal, not decades of varnish and debris.
• Factory-certified replacement parts. 8.0mm plunger-and-barrel assemblies, camshaft bearings, throttle shaft assembly, hand primer, and the correct gasket kit for your fuel system, sleeve-meter or New Scroll. We replace what needs replacing with factory-certified components, never cheap generic substitutes.
• Governor service. The governor shaft and weight carrier, in both the early and late style, are serviced and set so the engine holds its governed speed under load instead of hunting.
• Calibration and testing on real machines. The finished pump is mounted on a professional test bench and calibrated to Caterpillar specification. We set fuel rate, balance point, and governor settings, and we prove the pump before it ships.

That final step is what separates a real rebuild from a parts swap. Anyone can install a gasket kit. Very few shops can put a 3300-series pump on a bench, calibrate it to Caterpillar 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 fuel supply and clean, water-free fuel are essential to pump life, so we recommend fresh fuel filters at installation to protect your rebuild.

What a 3304 or 3306 Pump Rebuild Costs

Why Valley Fuel Injection

Valley Fuel Injection & Turbo is a full-service, factory-certified diesel fuel injection shop in Woodland, California, serving equipment owners, contractors, 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 injection pumps correctly, and we have been doing it long enough to have seen just about every 3300-series pump 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.

Not sure whether your hard start or low-power complaint is really the pump? Start with our in-depth injection pump timing symptoms guide, then give us a call and we will help you sort it out.

Frequently Asked Questions

How much does a CAT 3304 or 3306 injection pump rebuild cost?

Most CAT 3304 and 3306 injection pump rebuilds run between $2,350 and $3,800, with a typical rebuild around $2,900. Those figures come from real 3300-series jobs across our bench, not guesses. Pumps with heavier wear or hard-parts damage run toward the top of the range. We give you a firm quote after teardown and inspection, before any work begins. Call 530-668-0818 for current pricing.

Can I ship my pump to you from out of state?

Yes. This is a rebuild service for your own pump, and we rebuild pumps for customers nationwide. Remove the pump from the engine, pack it securely, and ship it to our Woodland, California shop, or drop it off in person. We tear it down, quote the job, rebuild and bench-calibrate the pump, and ship it back ready to install. Many 3300-series pumps arrive by freight from other shops and fleets.

What warranty comes with the rebuild?

Every pump we rebuild carries a 1-year warranty on the pump rebuild. Electrical and electronic components are warrantied for 30 days. We control every step in-house, from teardown to final calibration on the test bench, which is why we can stand behind the work. Clean, water-free fuel and fresh fuel filters at installation are essential to pump life and protect your rebuild.

Do you rebuild both the sleeve-metering and New Scroll versions?

Yes, we rebuild both. Caterpillar used a sleeve-metering fuel system on earlier 3304 and 3306 engines and moved to the New Scroll fuel system on later ones. The internals and gasket kits differ between the two, and we carry the correct parts and calibration specifications for each. If you are not sure which version your engine has, call 530-668-0818 and we will help you identify it.

How long does a rebuild take?

Turnaround depends on our current shop schedule and parts availability for your specific pump, so we give you an honest timeline when we quote the job. If a dozer, loader, or genset is down and every day of downtime costs you money, tell us when you call and we will do our best to prioritize your rebuild.

Is rebuilding my pump better than buying a replacement?

Almost always, yes. Many 3304 and 3306 pumps are decades old, and a matching replacement is expensive or simply no longer available. Rebuilding your own core keeps the pump matched to your engine, and our rebuild restores it to Caterpillar specification with the wear parts replaced and the calibration proven on the bench. It is usually faster and less expensive than hunting down a replacement of unknown history.

How do I know the pump is the problem and not something else?

Not every hard start or low-power complaint is the pump, so it is worth ruling out fuel supply, filters, and timing first. Our injection pump timing symptoms guide walks through which symptoms point to the pump. And once your pump is on our bench, the flow numbers tell the real story. We only quote the work your pump actually needs, and we tell you if it does not need a rebuild at all.