Description
Four independent parts sources describe this number as a hydraulic steering pump for the WA380-6 and WA430-6 class. That agreement is unusual in aftermarket data, and it is why we publish the circuit confidently here while still flagging what Komatsu’s own catalogue does not confirm.
Applicabilité et preuves
Komatsu WA380-6, WA430-6 and WA430-6E0 wheel loaders. 708-1U-00171 appears alongside it for the same machines, and no source we could check documents a supersession between the two, so we quote against your plate rather than assuming either fits. Komatsu’s online parts catalogue does not return a citable page for the number, so the item name is dealer and EPC-derived rather than manufacturer-confirmed, and no displacement or pressure figure is published for it here.
Why a steering pump fault gets blamed on the valve
Steering complaints on these loaders present as heaviness at low engine speed, or as a wheel that wanders when the machine is articulated under load. Both look like a control valve problem, and both are frequently caused by a steering pump that can no longer hold flow at idle. The distinguishing test is simple: measure steering pressure at idle and at rated rpm. If the shortfall tracks engine speed, look at the pump. If it does not, look at the valve and the priority flow divider.
The same machine also carries a main hydraulic pump, listed separately as 708-1W-00882, and a fan drive pump. Three pumps, three circuits, one machine: which one is failing is a measurement question, not a catalogue question.
Diagnosis order
- Check the steering relief and the priority divider before removing anything.
- Measure steering pressure and flow at idle and at rated rpm.
- Inspect the oil and the return filter; contamination is the usual root cause.
- Confirm the case drain line is unrestricted, since back-pressure finishes the shaft seal and the leak then gets blamed on the pump.
Notre guide d'achat et de spécification de pompe covers how to compare a replacement against the original specification.
Montage et commande
Match shaft spline, pilot, flange, port positions and the orifice or control arrangement against the removed pump, since steering pumps on these loaders vary by build option. Prime with clean oil before cranking, change the return filter element, keep the case drain unrestricted to tank, and target ISO 4406 18/16/13. Minimum order one piece. Three to six month warranty on new aftermarket units as stated on your proforma invoice; bench checked and photographed before the wooden case closes, delivery 5 to 8 working days from payment subject to stock. The WA600-6 steering pump is 708-1G-00041; la gamme se trouve sous Pompe hydraulique Komatsu.
