説明
On a C-series backhoe this pump is the machine. Everything the boom, stabilisers and loader functions do comes from it, so when it fades the whole tool slows down rather than one circuit. That makes diagnosis simpler than on an excavator, and it also makes an incorrect substitution more expensive.
What the catalogue and component data say
Caterpillar lists 161-6634 as a Slipper Piston Pump. Component cross-reference data identifies the underlying unit as a Bosch Rexroth variable displacement axial piston pump, catalogue R986110072. Cat’s own literature shows this number superseding 155-5109 and 155-5110, and trade listings pair it with the old-format number 0R-7793. A related pump, 112-6564, appears on the same 3054-engined backhoe line; it is a same-family item rather than a confirmed direct replacement, so treat it as a separate number until your parts book says otherwise.
Why the note in our own data saying 14T was dropped
The internal parts sheet for this item carried a shorthand of 14T. That is not a Caterpillar designation, and we could not match it to any published displacement, tooth count or size code for this pump. Rather than repeat it on a public page and let it become a specification, we have left it out. If your enquiry quotes 14T, send the photograph of the plate and we will identify the actual part.
Applicability
CAT 416C, 426C, 428C, 436C and 438C backhoe loaders with the Cat 3054 engine. Machine prefixes in Cat’s serial data include 1WR, 4ZN, 5YN and 1XR for the 416C, 1ER, 1CR, 1NR and 1MR for the 426C, 8RN and 2CR for the 428C, 9JN, 1RR, 1FR and 1PR for the 436C, and 1JR and 1TR for the 438C.
How a main pump fails on a backhoe
- All functions slow together, worst when hot. Internal wear across the slipper interface and valve plate. Flow test at full oil temperature, not cold.
- Noise and a foamy reservoir. Cavitation from a restricted suction line, a collapsed hose liner or a blocked strainer. The pump then wears itself out along the same path that starved it.
- One circuit weak, others normal. Usually not this pump. Look at the spool valve, the relief setting or the cylinder seals first.
- Shaft seal leak. Check the case drain routing before condemning the seal; back-pressure in the casing is the usual cause.
当社の pump buyer’s and specification guide covers how to compare a replacement against the original, and regulator diagnosis and adjustment covers the control side of a variable pump.
Fitting
Match shaft spline, pilot, flange, port positions and control orientation against the removed pump. Prime the casing with clean oil before cranking. Fit a new return filter element and clear the suction strainer. Route the case drain to tank unrestricted. Then measure pressure and flow against the machine specification and log the numbers, because a pump fitted without a baseline is impossible to claim against later.
Ordering
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 before the wooden case closes, delivery 5 to 8 working days from payment subject to stock. Related: 350-0666 for the E-series backhoes and 307-3063 for the F series. The range sits under CAT hydraulic pump.
