149 parts · 11 makes
Main Hydraulic Pumps
Main and charge pumps — the component whose failure takes the whole machine with it.
Know the part before you order.
The main pump feeds every circuit on the machine. When it fails it frequently sends debris downstream through the entire hydraulic system, which is why pump quality is not a place to economise.
Request a main hydraulic pump Find a dealer
Specified by DYCO: alloy grade, heat-treat target, seal and bearing grade. Country of origin, stated in writing. How a DYCO part is built →
Warranty — 1 year. Returns run 30 days from purchase, dealer to DYCO. A return and a warranty claim are different things — both are on the warranty and returns page →
Before you buy one
The pump, or the circuit it lives in?
A pump failure is a system job rather than a component swap. Something upstream usually kills it, and when it lets go it sends debris downstream through every circuit it feeds.
“Weak hydraulics” is not a pump diagnosis
Pressure and flow measured against the machine’s own figures is what identifies the pump instead of blaming it.
Slow, weak and hot is how a tired pump feels from the seat. It is also how a wrong relief setting, a worn control valve, a bypassing cylinder, a loaded filter and a restricted suction all feel. DYCO-TP-112 — Inlet Conditions, Cavitation and Aeration in Hydrostatic Pump Circuits →
When it lets go, it contaminates everything it feeds
Debris from a failed pump travels the circuit. A clean pump in a dirty circuit is a short warranty.
So the question after a pump failure is never only which pump. It is what the debris reached, and whether the lines, cooler and actuators were flushed and the filtration renewed before the replacement went on. DYCO-TP-106 — Fluid Cleanliness and Component Life in Closed-Circuit Hydrostatic Drives →
The inlet side decides how long a pump lives
A restricted suction, a low fill or a hose collapsing under suction starves the inlet. Vapor cavities then collapse against metal and erode the rotating group from the inside out.
Air drawn past a fitting does something similar by a different road. Neither is the pump’s fault, and neither goes away when the pump is changed. DYCO-TP-112 — Inlet Conditions, Cavitation and Aeration in Hydrostatic Pump Circuits →
Heat is the same failure, running slowly
Fluid that runs hot thins, loses film strength and oxidizes. The rotating group then wears at a rate the design never assumed.
The cooler, the fluid grade and the fill are part of the pump’s operating envelope, not separate housekeeping. DYCO-TP-106 — Fluid Cleanliness and Component Life in Closed-Circuit Hydrostatic Drives →
Case drain separates worn from blamed
Leakage past the rotating group leaves by the case drain. Flow there — against the machine’s figure, at temperature — is the measurement that settles it.
A pump within its figure is telling you the fault is somewhere else. Worth knowing before an order rather than after.
Qualify the replacement, then give it a clean circuit
Displacement, control type, port arrangement and drive arrangement all have to match. A replacement is worth what it can be shown to be rather than what the box says.
Then it goes into a circuit that has been put right — in that order. DYCO-TP-111 — A Qualification Framework for Non-OEM Drivetrain Components →
None of this is a rule of thumb: each one is a mechanism, and the publication beside it sets out the engineering it rests on.
Machine down? Start with the number on the tag.
Send the part and your machine to a dealer from here, or email the make and model and we will point you at one who stocks it.