YA00005829 is the number Hitachi assigns to the fan motor on a large group of mid-size Zaxis machines, and it is a number that gets ordered wrongly more often than almost any other in this catalogue. The reason is simple: the same excavator model can leave the factory with a KYB motor or with a Parker motor depending on build year and destination market, and the two are not interchangeable at the ports.<\/p>\n
The motor in these photographs carries a KYB Corporation Japan plate with three identifiers that matter to you:<\/p>\n
Supplied for Hitachi ZX470-3, ZX490-5A and ZX870-3 machines, and listed by the trade against ZX450, ZX450-3, ZX500, ZX850 and the Deere-Hitachi equivalents of the same tonnage classes. The confusion starts because Hitachi’s own parts numbers for this position overlap: 4634936 and 4634947 point at the Parker-built motor, while YA00005829 points at the KYB-built motor, and several suppliers cross-reference them as if they were one part. They are not the same physical unit. The Parker housing is a flat-topped rectangular casting with corner bolts; the KYB unit has a compact body with side mounting ears and the two work ports on the underside.<\/p>\n
Send a photograph of your old motor before payment and we will tell you which of the two you have. If it is the Parker type, the correct page is our 4634936 fan drive motor<\/a>. If you want the lower-cost Chinese-made equivalent of this KYB type, see YA00005829 replacement fan motor<\/a>.<\/p>\n Hitachi does not run the cooling fan from the engine through a belt and viscous coupling on these machines. The factory specification for the ZX470LC-6, the direct successor to the -3, describes a cool-on-demand, hydraulic-driven, suction-type fan with remote-mounted drive<\/em> und einem hydraulic fan reverser<\/em> in standard equipment. On the twin-fan ZX870-5G, Hitachi states that the system optimizes the rotational speed of two cooling fans, depending on the temperatures of coolant and hydraulic oil<\/em>, for cooling capacity and noise reduction.<\/p>\n Read those two sentences together and the diagnostic logic follows. Airflow is a function of hydraulic flow and of a control signal that watches two temperatures. A motor that has lost volumetric efficiency through internal wear produces exactly the same symptom as a fan pump that cannot reach full displacement, or a fan valve stuck part-way. Before you buy a motor, measure. Hitachi’s technical manual for the -6 series lists the tests by name: fan pump P-Q diagram, fan pump flow rate measurement, fan pump delivery pressure, fan motor drainage and fan valve inspection. Our hydraulic fan motor diagnosis guide<\/a> covers the same ground with equipment a normal workshop has.<\/p>\n Three things, in this order. Contamination, because a gear motor’s clearances are small and the fan circuit is usually the last place anyone thinks to flush. Case drain back-pressure, because the drain line is often routed badly when a radiator or fan guard comes off; the published limit for axial piston units of this size band is 0.1 MPa in normal running and 0.4 MPa at peak, and a gear motor will not tolerate much more. And heat, because oil running hot thins the film and the unit then wears faster each hour it runs. Cleanliness target for this class of component is NAS 1638 class 9, which is ISO 4406 18\/15, with a 10 micron return filter.<\/p>\n If the machine has already swallowed a motor, read the seal kit rebuild scope checklist<\/a> und drive gear inspection<\/a> before you put a good unit back into a dirty circuit.<\/p>\n This grade arrives as original-equipment surplus and as pulled units from machines being broken in Japan, which is why we sell it without warranty: we cannot stand behind a service history we did not see. What we do guarantee is the identification. Every unit is bench-checked for shaft rotation and drain condition, photographed, and matched to the plate numbers quoted above before it is packed in a wooden case. Minimum order one piece. Stock moves in single units rather than batches, so if you need two or three for a fleet, send the enquiry early and we will hold what is on the bench.<\/p>","protected":false},"excerpt":{"rendered":" Part:<\/strong> YA00005829 hydraulic fan motor for Hitachi ZX470-3, ZX490-5A and ZX870-3 excavators, supplied as Japanese-production KYB stock.<\/p>\n What the plate on this unit reads:<\/strong> KYB Corporation Japan, MSF-50-45, internal part B0440-50016, serial 560021.<\/p>\n Terms:<\/strong> genuine-type grade, sold without warranty as with all original-equipment and used stock. A Chinese-made equivalent with a three to six month warranty is listed separately.<\/p>","protected":false},"featured_media":4279,"template":"","meta":[],"product_brand":[],"product_cat":[571,37],"product_tag":[552,152,279,578,577,298,579],"class_list":["post-4320","product","type-product","status-publish","has-post-thumbnail","product_cat-hitachi-fan-motor","product_cat-hydraulic-fan-motor","product_tag-fan-motor","product_tag-hitachi","product_tag-kyb","product_tag-msf-50-45","product_tag-ya00005829","product_tag-zx470-3","product_tag-zx490-5a","first","instock","shipping-taxable","product-type-simple"],"_links":{"self":[{"href":"https:\/\/www.hongtengdaparts.com\/de\/wp-json\/wp\/v2\/product\/4320","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hongtengdaparts.com\/de\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/www.hongtengdaparts.com\/de\/wp-json\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.hongtengdaparts.com\/de\/wp-json\/wp\/v2\/media\/4279"}],"wp:attachment":[{"href":"https:\/\/www.hongtengdaparts.com\/de\/wp-json\/wp\/v2\/media?parent=4320"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/www.hongtengdaparts.com\/de\/wp-json\/wp\/v2\/product_brand?post=4320"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/www.hongtengdaparts.com\/de\/wp-json\/wp\/v2\/product_cat?post=4320"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/www.hongtengdaparts.com\/de\/wp-json\/wp\/v2\/product_tag?post=4320"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}How the fan circuit on a Zaxis actually works<\/h2>\n
What kills these motors early<\/h2>\n
Sourcing note on Japanese-production stock<\/h2>\n