A tractor with a CAV DPA pump may be decades old, but it still has work to do. The DPA is a smart compact distributor design – and an excellent example of why accurate calibration matters on classic diesels. Customers across the country can use our mail-in inquiry process to determine available testing, repair, rebuilding and calibration options for the exact unit.
What is the CAV / Lucas-CAV DPA system?
CAV DPA is a rotary distributor pump family with a long history across agricultural and industrial diesel applications. Branding may appear as CAV, Lucas CAV, Lucas or other historical variants, depending on the unit. These names help identify the lineage, not a guaranteed parts interchange. Send a photograph of the nameplate and governor/control side, especially if the tractor has had an engine or pump swap.
Common symptoms and what else to check
Hard starting, leakage, rough idle, smoke, loss of power and problems after long storage may justify an evaluation. Also check the tank, filters, lift-pump supply, air in fuel, engine timing and injector condition.
How to investigate a suspected DPA pump problem
Identification depends on the complete DPA nameplate and engine application. Appropriate work may include inspection for wear and leakage and performance evaluation against the correct pump test data.
Repair, rebuild or replacement: making the right call
A rebuild or repair should match the actual variant and calibration requirement. Do not choose a random DPA pump because the outlet count and flange look right.
Other names and numbers to look for
The most useful search terms for this family include: CAV DPA; Lucas CAV DPA; Lucas DPA; Delphi DPA for historical references; Rotodiesel DPA on certain applications.
CAV DPA design, applications and diagnosis
How the DPA Works
Picture a lazy Susan at a farmhouse dinner: one spinning center serves everybody at the table in turn. The DPA’s rotor does that with fuel.
- Transfer pump. Vanes on the end of the rotor raise incoming fuel to a regulated pressure.
- Metering. The governor positions a metering valve that sets how much fuel enters the rotor.
- Pumping. Rollers ride an internal cam ring. Each lobe pushes the opposed plungers together and builds injection pressure.
- Distribution. A port in the rotor lines up with each outlet in the hydraulic head and sends fuel to that cylinder.
Depending on the version, the governor is mechanical or hydraulic, and some DPAs add an automatic advance. Fuel lubricates the whole pump.
Shop Talk: The hydraulic head is the stationary block the rotor spins inside, with one outlet per cylinder. Rotor and head are a matched pair with clearances finer than a hair, so if one is scored, both are replaced together.
What It Fits
| Make and model | Engine | Years | Notes |
|---|---|---|---|
| Massey Ferguson 135 | Perkins AD3.152 | 1964-1975 | Diesel versions only |
| Massey Ferguson 150 | Perkins diesel | Diesel versions only | |
| Massey Ferguson 230, 235, 240, 245, 250 | Perkins 3- and 4-cylinder | Engine varies by model | |
| Ford 3500 to 4610 range, such as 3600, 4600 and 4610 | Ford 3- and 4-cylinder diesel | Read the tag before ordering | |
| Ford 5000, later production | Ford 4-cylinder diesel | Earlier 5000s used the Simms Minimec | |
| Perkins-powered equipment | Perkins 1004 | Some 1004s use DP200 or Stanadyne pumps |
More on our Massey Ferguson and Ford tractor page and Perkins and Cat page.
Part Numbers We See
DPA numbers start with four digits and a letter, like 3233F390. Common families include 3230F, 3233F, 3340F and 3342F. The number is on a small plate riveted to the pump body, often with a second line of setting code.
Some pumps also carry a Massey Ferguson, Ford or Perkins part number. Send whatever you can read; one clean number is usually enough to find the calibration.
Owner’s Tip: Old plates hide under paint and grime. Wipe with a rag and a little solvent instead of scraping, then photograph the plate straight on. If it is unreadable, send the tractor model and engine serial number instead.
Why DPAs Fail and the Symptoms
- Water from condensation in half-empty tanks rusts the rotor, plungers and head.
- Dirt and stale fuel wear the transfer vanes and leave varnish that sticks the metering valve and governor.
- Drive shaft seals wear and can leak diesel into the engine oil.
- Throttle and stop shaft seals harden and weep.
- Worn rollers, shoes and cam ring cut delivery and upset timing.
Symptoms:
- Hard starting, especially when the engine is hot
- Stalling at idle or dying when the loader goes up
- White or black smoke, or low power on the PTO
- Hunting or surging
- Fuel weeping from the pump
- Engine oil level rising and smelling of diesel
- Engine that will not shut off with the stop control
Leaky pump? Our injection pump leaks guide covers where fuel shows up and why.
Details that make a cav dpa inquiry useful
A CAV DPA often arrives after years of service on agricultural or industrial equipment. The full plate number, governor details and engine model determine much more than the CAV or Lucas name alone. Mention long storage, fuel seepage, stuck throttle linkage or any previous timing adjustment. These observations help distinguish a limited defect from a pump that needs wider inspection.
Frequently asked questions
Can a CAV / Lucas-CAV DPA injection pump be rebuilt?
Whether CAV / Lucas-CAV DPA is a good repair candidate depends on sound housings, wear on precision components, the correct service parts and reliable model-specific test information. A leak, sticking from storage, or debris in the fuel may point to very different work. The right recommendation follows the evidence on the identified assembly—not the appearance of a similar pump. Discuss the exact unit.
Will a DPA pump from another engine fit mine?
Identification trap with CAV / Lucas-CAV DPA: Similar castings do not establish interchange. Engine rating, governor and advance controls, electrical arrangements and part-number suffixes can change the specification. Compare the full tag and application before discussing replacement, calibration or installation. Use the identification guide.
Request CAV / Lucas-CAV DPA Service Information: Start your repair inquiry
How mail-in service works | Browse pump families
CAV DPA: the complete tag matters on older working equipment
DPA pumps appear on a range of legacy farm and industrial engines. Linkage and governor behavior, exact calibration, contamination history and engine-side timing may matter more than a superficial match to a neighboring DPA model. Record the plate and installation context before service.