Description
Most workshops do not want a debate about whether the original fan motor was made by KYB or Parker. They want the machine running by Thursday and someone to stand behind the part if it fails. That is what the replacement grade of YA00005829 is for, and this page exists so you can decide between the two grades with the differences written down rather than discovered on the bench.
Genuine-type stock against our replacement, side by side
| Point of comparison | Japanese-production YA00005829 | This Chinese-made replacement |
|---|---|---|
| Identification on the unit | KYB plate reading MSF-50-45, part B0440-50016, Made in Japan | Factory sticker with model and part reference; cast and machined identification on the housing |
| Housing | Compact body with side mounting ears | Black body with silver top cover and four-bolt square flange |
| Work ports | Two ports on the underside | Two ports on the underside, M22 x 1.5 thread |
| Shaft | Smooth shaft with the KYB hub arrangement | Keyed shaft |
| Warranty | None, as with all genuine and used stock | Three to six months as stated on the proforma invoice |
| Supply continuity | Single units as surplus arrives from Japan | Around 1,000 pieces a month, fleet quantities available |
| Price position | Higher, and it moves with the surplus market | Quote on request, normally the lower of the two |
Read the housing rows carefully. These are different physical parts, not the same part from two suppliers, which is why we do not treat the two listings as interchangeable and neither should you. If your machine has the flat-topped Parker unit, the page you want is our 4634936 fan drive motor.
Where it fits
Listed for Hitachi ZX450-3, ZX470-3, ZX850-3 and ZX870-3, which is the -3 generation of the 45 to 87 tonne range. The same YA00005829 number appears in trade data against ZX490-5A and ZX870-5A machines, and against Deere-Hitachi builds of the same tonnage. Later -5B, -5G and -6 cooling packages use different assemblies, so the machine serial prefix decides, not the model badge.
What a replacement fan motor has to survive
The cooling circuit on a Zaxis machine is a controlled system, not a simple oil feed. Hitachi’s specification for the ZX470LC-6 describes a cool-on-demand, hydraulic-driven, suction-type fan with remote-mounted drive plus a hydraulic fan reverser, and on the twin-fan ZX870-5G the factory states that fan speed is optimised from both coolant and hydraulic oil temperature. In practice that means the motor spends its life cycling between low and full displacement demand, in oil that is often hotter than it should be, in a circuit that was contaminated the day the previous unit failed.
Which brings us to the honest part of selling a replacement. A new motor fitted to the oil that destroyed the old one will fail early, and the claim will look like a bad part. So before this unit goes on:
- Flush the fan circuit and the case drain line. Do not skip this because the machine has work to do.
- Change the return filter element. The published target for this class of component is NAS 1638 class 9, which is ISO 4406 18/15, with a 10 micron return filter and an 80 to 150 mesh suction strainer.
- Confirm the case drain runs free to tank. Keep it within the 0.1 MPa normal and 0.4 MPa peak limits published for axial piston units of this size, since a pinched drain is the standard cause of a weeping shaft seal.
- Prove the fan reaches full speed under thermal load after fitting, and check the reverser still works. If it does not, the fault is upstream and the new motor is not the end of the diagnosis. Start with our fan motor diagnosis guide.
Ordering and terms
Minimum order one piece, and fleet orders are welcome because this grade is stocked rather than sourced one at a time. Each unit is bench-checked for rotation and drain condition, photographed against your order, then packed in a wooden case or to your specification. Delivery is 5 to 8 working days from payment subject to stock, by sea or air for volume, or DHL, FedEx, TNT and EMS for single units. Payment by L/C, T/T, PayPal or Western Union.
If the pump feeding this motor is also tired, the fan pump for the same machine is listed under 4633474 K3V63S fan pump, and the remanufactured YA00006715 assembly is on our Hitachi fan pump page. Other Hitachi wear parts are in the Hitachi parts section.
