A hydraulic gear pump may have the right general shape and still be wrong for the machine. Small differences in displacement, rotation, shaft geometry or port threads can prevent installation—or create a serious operating mismatch. For US distributors supporting mixed fleets, the following five data groups make a replacement request faster and more reliable.

1. Displacement, flow and speed

Provide the pump displacement per revolution when known. If the available information is flow, include the speed and operating point at which it was measured. List the normal input speed, maximum speed and expected flow range. These values need to be reviewed together; a flow value without speed does not define the pump size.

2. Direction of rotation

State clockwise or counterclockwise rotation as viewed from the drive-shaft end, and confirm which port is inlet and which is outlet. Include a marked photograph if there is any uncertainty. Rotation conventions can be misunderstood when the viewing direction is not stated.

3. Shaft and mounting geometry

Record the mounting standard or provide the pilot diameter, bolt spacing and flange thickness. For the shaft, identify whether it is keyed, splined, tapered or another form, then add the diameter, usable length and spline details where applicable. A side photograph with a scale and a dimensioned sketch are often more useful than a single front view.

4. Port size and thread form

Measure the inlet and outlet separately and identify the connection type. NPT, SAE straight-thread O-ring, BSP and metric threads are not interchangeable even when their nominal sizes appear close. Note port position and orientation as well, because hose clearance can matter as much as the thread itself.

5. Pressure, duty and fluid conditions

List normal and peak pressure, duty cycle, oil type and viscosity grade, expected oil-temperature range, ambient conditions and filtration information. Also mention whether the pump drives a continuous function or sees frequent pressure spikes. This gives the technical team a better picture of the application than a maximum-pressure number alone.

Finish the RFQ with all readable nameplate markings, the machine model, the original pump reference, several clear photos and any available drawing. Use consistent units and identify unknown values openly. CKEY can then separate confirmed requirements from items that still need measurement, reducing the risk of a guess-based substitution.