Descrição
This listing corrects an error in our own parts data, and the correction changes what the part is. The folder description called 187-9090 a fan motor. Caterpillar’s parts book calls it PUMP GP-PISTON -BRAKE, a member of the brake pump and mounting group 152-6961, and the catalogue title gives it a displacement of 18Cc. An 18 cm3 variable piston pump is exactly the size Cat uses for brake and auxiliary supply duty, and far too small to drive the cooling fan on a 40-tonne truck.
How the fan label got attached
Cat documents the 735 and 740 fan drive in manual RENR5126, and the circuit is built from a gear pump and a gear motor, regulated by a coolant-temperature valve with relief, check and bypass valves. On the 735 the fan pump is driven from the top of the transmission; on the 740 it is driven at the rear of the steering piston pump. The same text locates the fan and steering gear pump below the brake piston pump, which is the sentence that settles it: on these trucks there is a brake piston pump and a separate fan engrenagem pump, and 187-9090 is the piston one.
The fan wording came from supplier titles that print both in one line, such as ‘Brake Pump GP Piston for 735 735B 740 740B Fan Pump’. That is search-term stuffing, and it is how workshops end up with a brake pump in a fan-circuit enquiry.
Applicability
CAT 735 from prefix B1N 00001, 740 Ejector Truck at B1R 00001, and 740B at L4E 00001, on the 3406E generation. The 735B prefix is not individually booked in the material we checked, so treat it as confirm by PIN. Do not attach C13 or C15 engines to these prefixes; the current Cat 735 and 740 are a different machine on different engines, and their pumps are different parts.
What not to cross
224-4432, reman 10R-4355, is the main hydraulic piston pump on the same trucks. It is a different circuit, a different displacement and a different price. Any listing that offers 187-9090 and 224-4432 as interchangeable has not read the parts book, and a machine fitted with the wrong one will either have no brake reserve pressure or no implement power.
Failure signs on a brake supply pump
- Brake accumulation pressure falling, or the secondary brake warning appearing under load: test the supply pump output before touching the accumulators.
- Steering heavy with normal implement function: check whether the steering and fan gear pump is the fault, not this pump.
- Oil at the shaft: case drain back-pressure first.
Nosso regulator diagnosis and adjustment guide covers compensator testing on variable piston pumps generally, and the seal kit rebuild checklist covers rebuild scope.
Fitting and ordering
Match shaft spline, pilot, flange, port positions and the compensator setting against the removed pump. Prime the casing with clean oil before cranking. Change the return filter element and clear the suction strainer, targeting ISO 4406 18/16/13. Keep the case drain unrestricted to tank. On a brake circuit, confirm accumulator charge and warning-lamp behaviour before the machine returns to work.
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. The range sits under CAT hydraulic pump.
