When you have replaced the pump head of a dispenser pump but the pump still binds, you should:

The correct approach in this scenario involves addressing the alignment and fit of the components after replacing the pump head. Increasing the number of gaskets under the head can help ensure that there is enough clearance between the rotor, idler gear, and other internal components.

When the pump binds, it typically indicates that there is not enough space for internal parts to move freely, which could be due to improper alignment or insufficient spacing caused by modifications or wear. By adding additional gaskets incrementally, you can achieve the right amount of clearance, thereby preventing binding and allowing the pump to function smoothly without unnecessary friction.

However, it’s important to note that simply increasing gaskets should be done carefully, checking the pump’s operation regularly to prevent over-spacing, which could lead to other issues such as loss of pressure or inefficient operation. The goal is to attain a balance where the pump operates efficiently without any parts obstructing its movement.