Descrizione
When a buyer searches 4634936 they are usually trying to settle one question: is the machine’s original fan motor a Parker unit or a KYB unit? On the Zaxis 450 to 870 class the honest answer is that both appear, because Hitachi sourced the fan drive from more than one supplier across build years and markets. This page covers the Parker-built side of that split.
What the nameplate on this unit says
We photograph what we ship rather than describing a generic part. The units in these images carry a Parker Denison plate with:
- Modello: M5BF 045, which places it in Parker’s bent-axis motor family rather than in a gear-motor family.
- Code: 024-94578-0 on one unit and 024-94702-003 on the second, with serial numbers 12L03 338 and 202301240082.
- Origin marking: Made in France, consistent with the Denison lineage Parker inherited.
- Housing castings reading 994-67078 H and 34-37650-0, numbers that also appear in Deere-Hitachi forestry parts lists.
That last point explains something that confuses buyers: the same motor is sold as a John Deere part for 470G, 670G and 850D harvesters, because those machines are Deere-Hitachi builds. If you are fitting this to a forestry machine rather than an excavator, the plate numbers are what matter, not the badge on the cab.
Where this motor is fitted
Trade parts data and our own order history attach 4634936 to the ZX450-3, ZX470(H)-3, ZX470LC-5B, ZX500LC-3, ZX520LCH-3, ZX670LC-5B, ZX850-3, ZX870(H)-3, ZX870-5B and ZX870-5G, plus the TL1100-3 lift truck and ZX1800K-3. Treat that as a starting list, not a guarantee: Hitachi changed fan drive suppliers between generations, and the -5B and -5G machines use different control arrangements from the -3. The number stamped on your own housing decides it.
Why the fan motor is blamed for heat faults it did not cause
Hitachi’s own specification for the ZX470LC-6 describes the cooling arrangement as a cool-on-demand, hydraulic-driven, suction-type fan with remote-mounted drive, and lists a hydraulic fan reverser in the standard equipment. Two consequences follow. First, the fan is not belt-driven, so a slipping belt is never the explanation on these machines. Second, airflow is metered hydraulically, so a heat complaint can start at the pump, at the fan valve, at the reverser, or at the motor. Replacing the motor first is how yards end up with a good spare part and the same overheating.
Hitachi publishes the tests for exactly this circuit in its technical manual for the -6 series: fan pump P-Q diagram, fan pump flow rate measurement, fan pump delivery pressure, fan motor drainage, and fan valve checks. If your workshop has access to that manual, run those tests before ordering. If you do not, our hydraulic fan motor diagnosis guide walks through the same logic with a pressure gauge and a flow meter.
Fitting notes that protect the new motor
Kawasaki’s installation data for axial piston units of this class gives two limits worth writing on the work order: casing drain pressure should stay below 0.1 MPa in normal running and 0.4 MPa at peak, and the oil should be held to NAS 1638 class 9, which is ISO 4406 18/15, with a 10 micron return filter and an 80 to 150 mesh suction strainer. A restricted drain line and a full return filter are responsible for most early claims we see on fan motors.
When you remove the old motor, catch the case drain oil separately and look at it. Grit and shiny particles mean the circuit needs flushing before a replacement goes in, otherwise the new unit inherits the debris that killed the last one. The reverse function should be proven after fitting, not ignored: see why hydraulic oil still runs hot after all the wear parts have been replaced for the check valve inspection that follows on from this job.
Verification steps before you pay
- Photograph the nameplate on your old motor. If it reads Parker M5BF, this is the correct listing. If it reads KYB MSF, go to our YA00005829 KYB fan motor page instead.
- Send the machine serial number. It tells us which of the three cross numbers applies to your build.
- Confirm shaft form and flange bolt pattern against the photographs on this page.
- Decide whether you need warranty. Japanese-production stock is sold without warranty; the Chinese replacement version of this motor carries a three to six month warranty.
- Check the pump side. If your fan pump is the YA00006715 remanufactured unit, the pairing is correct for most -3 and -5A machines.
Watch the real unit on our inspection video before ordering. Stock of this grade varies with what comes out of Japan; minimum order is one piece and every unit is photographed against your order before packing. Browse the rest of the range under motore idraulico del ventilatore or the Hitachi parts section.
