Description
The plate on the unit in our photographs reads PISTON PUMP, 350-0666, code 54789671, made in China, with a rotation arrow cast into the body. That matches Caterpillar’s own designation for this number, and it is the reason the fan pump label from our incoming data has been corrected on this page.
What the catalogue says
350-0666 is listed by Caterpillar as a Hydraulic Piston Pump, with the parts book item name PUMP GP-PISTON recorded under the hydraulic system section of the 434E. There is no FAN qualifier in either reference. Component data identifies it as a variable displacement axial piston unit, and Cat’s literature shows it superseding 296-6714 and 247-7867.
Applicabilité
CAT 414E, 416E, 422E, 428E and 434E backhoe loaders with the Cat C4.4 engine, the 434E covered from machine prefix SEF 00001 in the parts literature. The supplier cross 335-8197 that appears in our incoming data could not be confirmed against Cat applicability, so it is not published as a replacement number here. If your old pump carries 335-8197, send the photograph and we will identify it before quoting.
Supersession, and how to use it
When Cat lists a chain such as 296-6714 to 247-7867 to 350-0666, the later number is the one to order for a machine in that serial range, but the earlier numbers stay valid as search terms for machines that left the factory with them. Two practical rules follow. Search by the number on your own pump first, because that reflects what is physically fitted. Then check the machine serial prefix against the parts catalogue, because a previous owner may have fitted a later pump and a bracket or hose may not match.
Failure signs on an E-series backhoe
- All functions slow, worse hot: internal wear in the pump. Test flow at working temperature.
- Noise plus foam in the reservoir: cavitation. Check the suction hose and strainer before condemning the pump.
- Shaft seal leak: check case drain back-pressure, then the coupling alignment.
- One circuit only: spool valve or relief setting, not the pump.
Notre guide d'achat et de spécification de pompe couvre comment comparer un remplacement à l'original, et diagnostic de défaillance du boîtier de transfert covers the drive side that starves good pumps.
Montage et commande
Match shaft spline, pilot, flange, port positions and control orientation against the removed pump, and confirm rotation direction against the cast arrow. Prime the casing before cranking, change the return filter element, keep the case drain unrestricted to tank, and target ISO 4406 18/16/13 for the piston components in the circuit. Minimum order one piece. New aftermarket units carry a three to six month warranty as stated on your proforma invoice. Bench tested, photographed against your order, wooden case, delivery 5 to 8 working days from payment subject to stock. Related: 307-3063 for the F series and 161-6634 for the C series, under Pompe hydraulique CAT.
