Diaphragm Pump Parts

Provide brand, model and serial number. If the plate is unreadable, measure the diaphragm outside diameter (OD) and the inner bolt‑circle diameter and count clamp‑ring bolts. Photos of the clamp ring and seats help confirm fit.

Typical guidance (application dependent): Buna‑N ≈ 10–180 °F; Neoprene ≈ 0–200 °F; TPE/Santoprene commonly up to ~200 °F; Rubber often up to ~180 °F. Always check the specific part page.

Use Buna‑N for hydrocarbons (oily water, diesel, kerosene). Neoprene for general water service. TPE for long‑life where oils are minimal. Rubber for economy, non‑oil applications.

Hard starting/no prime, weak stroke, reduced flow, oil‑swollen or stiff diaphragm, visible cracks/tears or fabric showing. Replace immediately and inspect flappers and seats.

Yes. Replacing flappers with the diaphragm restores priming, suction lift and discharge check‑valve sealing, preventing backflow at shutdown.

Look for cupping/warping, nicks on the edge, embedded debris, or a shiny seat imprint. Backflow at shutdown or slow prime are typical symptoms.

If seats are chipped, grooved or corroded, replace them with the flappers. Clean seats thoroughly; debris on the seat is a common leak source.

Intake and discharge flappers are not interchangeable. Follow arrows/markings and hinge location. The flap must close against the seat in the direction of flow to seal.

Tighten evenly in a cross/“star” pattern to the OEM torque spec. Re‑check after the first run; uneven torque causes air leaks and weak priming.

Use new gaskets for sealing. Avoid petroleum‑based lubricants. If the OEM allows, a light film of clean water or mild soapy water can aid assembly—never use adhesive unless specified.

Often yes. Ensure chemical/temperature compatibility and the same bolt pattern and stroke depth. Choose Buna‑N for oil/fuel exposure; use TPE for long life when oils are minimal.

Likely chemical incompatibility or elevated temperature. If oils/fuels are present, switch to Buna‑N. Replace any flappers/gaskets exposed to the same fluid.

Store flat in a cool, dry area away from sunlight and ozone sources (motors, welders). Keep bagged and labeled to prevent contamination and compression set.

Inspect at regular service intervals or any time priming/flow declines. Many users inspect quarterly in heavy service; replace at the first signs of wear.

Check for air leaks at the clamp ring and gaskets, verify flapper orientation, confirm clean seats, and ensure the suction hose/strainer is airtight.

Yes. Some families have revisions (e.g., Wacker 0089596 supersedes 5000089596). Always verify your serial range before ordering.

Model‑specific intake and discharge flappers, weights/springs (if used) and new gaskets. We’ll confirm contents for your exact model.

Only if threads are clean and free of corrosion. Replace damaged hardware, tighten evenly and re‑check after the first run.

Brand, model, serial, discharge size (2″ or 3″) and a quick photo of the clamp ring/bolt pattern. We can usually confirm in one call or email.