Aquamite / Supastream Pump Brass Shim

Precision Spacing Component for Optimal Pump Performance

As a retailer of pool and spa parts, I stock this small but essential brass shim designed for Aquamite and Supastream pumps. This precision-engineered component ensures correct spacing between pump components, maintaining optimal impeller clearance and preventing performance issues.

What is a Pump Brass Shim?

A brass shim is a thin, precisely manufactured washer that fits onto the motor shaft between the impeller and seal plate. Its purpose is to adjust the exact position of the impeller within the pump housing, ensuring the correct clearance between the impeller and the diffuser (the stationary component that directs water flow).

Made from brass rather than steel or other metals, these shims resist corrosion from pool chemicals and maintain their dimensions even when exposed to water and sanitizers. Brass doesn’t rust, making it ideal for the wet environment inside a pump.

Why Impeller Clearance Matters

The gap between the spinning impeller and the stationary diffuser is critical to pump performance. Too much clearance allows water to recirculate internally rather than being pushed through the system, reducing efficiency and flow rate. The pump works harder but delivers less water, wasting energy and failing to circulate the pool properly.

Too little clearance causes the impeller to drag against the diffuser, creating friction, heat, and noise. In severe cases, contact between these components can damage both parts, requiring expensive repairs. The grinding noise from metal-on-metal contact is unmistakable and indicates immediate attention is needed.

How Shims Adjust Clearance

Shims work by taking up space on the motor shaft. When you thread the impeller onto the shaft, it tightens down until it contacts the shim(s). Adding shims moves the impeller slightly away from the motor, increasing the gap between impeller and diffuser. Removing shims brings the impeller closer to the diffuser, decreasing the gap.

Most pumps require specific clearance—typically between 0.010 and 0.030 inches, though specifications vary by model. Manufacturers often provide multiple shims or shims of different thicknesses to achieve the precise spacing needed for optimal performance.

When Shims Are Needed

Shims become essential during pump assembly or rebuild. When installing a new impeller, motor, or seal plate, you must establish correct clearance. Without shims, the impeller might sit too close to or too far from the diffuser.

If you’ve replaced the mechanical seal, the new seal may have slightly different dimensions than the old one, affecting impeller position. Adding or removing shims compensates for these small variations, maintaining proper clearance.

Over time, component wear can also change clearance. If your pump has lost performance or developed noise, incorrect impeller clearance might be the culprit. Adjusting shims during maintenance can restore proper spacing and performance.

Checking Impeller Clearance

To check clearance, you need to access the impeller. With the pump disassembled, position the impeller on the shaft (without tightening it completely) and measure the gap between the impeller back shroud and the seal plate or diffuser. A feeler gauge provides precise measurements.

If clearance is incorrect, add or remove shims as needed. Each shim changes the gap by its thickness—typically 0.005 to 0.010 inches per shim. Make small adjustments, reassemble, and recheck until achieving the specified clearance for your pump model.

Installation Tips

Shims install between the impeller and the seal components on the motor shaft. They must sit flat and centered on the shaft. Keep shims clean—any debris or corrosion on the shim surface affects the final clearance measurement.

When tightening the impeller onto the shaft, ensure it threads down evenly against the shims. Cross-threaded impellers won’t seat properly, giving false clearance readings. The impeller should spin freely by hand without dragging or excessive wobble.

Some pumps use a single thick shim, while others use multiple thin shims stacked together. Using multiple shims provides flexibility—you can add or remove individual shims to fine-tune clearance without needing different sized parts.

Material Benefits of Brass

Brass offers several advantages for pump shims. Its corrosion resistance means the shim maintains its thickness over years of service. Steel shims can rust, gradually becoming thinner and changing clearance over time. Brass eliminates this concern.

Brass is also relatively soft compared to steel, which protects harder components like the impeller shaft. If the shim does wear, it wears instead of the more expensive shaft. Additionally, brass conducts heat well, helping dissipate any heat generated at the seal area.

The material’s durability means brass shims rarely need replacement unless lost during maintenance. If you’re disassembling your pump, keep track of shims carefully—they’re small and easy to misplace.

Compatibility

This brass shim is specifically sized for Aquamite and Supastream pump models. The inner diameter matches the motor shaft diameter, while the outer diameter and thickness are designed to work with these pump configurations. Using the correct shim ensures proper fit and accurate clearance adjustment.

These compact pumps are widely used in residential pools and spas, making the brass shim an important part to have available during maintenance or rebuilds.

Product Specifications

Specification	Details
Product Type	Brass Shim / Spacing Washer
Compatibility	Aquamite and Supastream pumps
Function	Impeller clearance adjustment
Material	Brass (corrosion-resistant)
Application	Installed on motor shaft between impeller and seal plate
Installation Location	Motor shaft assembly
Weight	0.01 kg
Dimensions (L × W × H)	0.1 m × 0.15 m × 0.15 m
Volume	0.002 cubic meters
SKU	6497240269
Category	Pool & Spa Spares

Maintenance Considerations

During any pump maintenance involving impeller removal, note how many shims were present and their position. This information helps you reassemble with correct clearance. If you’ve lost count or the shims, refer to your pump’s service manual for the recommended configuration.

Keep spare shims on hand—at this modest cost, having extras available during pump service prevents delays. If you discover incorrect clearance mid-assembly, having additional shims lets you make immediate adjustments rather than ordering parts and waiting.

After reassembly, listen to your pump during operation. Smooth, quiet running indicates proper clearance. Grinding, rattling, or excessive noise suggests clearance issues that need investigation. Reduced flow or pressure readings can also indicate clearance problems affecting hydraulic performance.

This small brass component plays a vital role in maintaining optimal pump performance, ensuring your Aquamite or Supastream pump operates efficiently and reliably season after season.