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Repair

Diaphragm Pump Rebuild on a 1000L Trailer Sprayer

Pressure had dropped off to almost nothing mid-season. A full strip, new diaphragms and valve kit, and the unit was back on the paddock the next day.

Rebuilt diaphragm pump on the workshop bench

Placeholder post. Replace with a real repair job — before and after photos work well here.

The problem

The owner rang saying the sprayer had gone from a solid working pressure down to a dribble, and the pressure gauge was bouncing all over the place. Classic symptoms of a failed diaphragm, with oil in the sight glass looking milky — a good sign water had got past.

What we found

Once it was on the bench and stripped down:

  • Two of the six diaphragms split, one badly
  • Valve seats pitted from an abrasive wettable powder mix
  • Suction strainer completely blocked, which is what had been loading the pump up in the first place
  • Oil contaminated and well overdue for a change

Pump stripped down on the bench

The repair

Full rebuild kit — diaphragms, valves, seats and O-rings — plus a new suction filter and a fresh oil fill. We pressure-tested it on the bench, then refitted and ran it up on the trailer to check flow against the nozzle output.

Worth knowing

Blocked suction filters kill more pumps than anything else we see. A two-minute check before each fill is the cheapest insurance going. We keep rebuild kits on the shelf for the common pumps, so most of these turn around in a day or two.

Pump not pulling like it should? Give us a call before it takes the rest of the unit with it.

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