How to Lubricate and Maintain a 1250 Body Masterstream Nozzle

Firefighting nozzles are built to take a beating, but like any piece of high-performance equipment, they need regular care to keep them working smoothly. Over time, dirt, debris, and heavy use can cause stream adjustment to bind up or degrade stream quality. Fortunately, basic field maintenance and lubrication on the 1250 body Masterstream nozzle is simple and helps extend service life.

When to Perform Field Maintenance

Field lubrication may be needed if you notice:

  • Resistance when switching between stream patterns
  • Debris buildup inside the nozzle

If either of these symptoms show up, it’s time for a quick inspection and lubrication.

Step 1: Disassemble the Nozzle

  1. Remove the nozzle from the apparatus.
  2. Inspect the inside for debris and clear any you find.
  3. Put the nozzle in full fog position.
  4. Unthread the front end carefully. Keep a hand on it since it’s under spring pressure.
  5. Remove the pieces, taking care not to lose the white Teflon washer.
  6. Pull out the pressure control unit.

Step 2: Choose the Right Lubricant

Use only non-penetrating lubricants, such as:

  • Break Free CLP (recommended)
  • Remington gun oil
  • Similar non-penetrating oils

Avoid penetrating lubricants like WD-40 or PB Blaster. These can swell O-rings and cause long-term damage.

Step 3: Apply Lubrication

Hit the following key points with lubricant:

  • Down the center of the shaft
  • On the control rod of the pressure control unit
  • Around the O-ring and its mating surface inside the nozzle
  • Along the shaft itself

Step 4: Reassemble the Nozzle

  1. Make sure all components (including spacers, if equipped) are in place.
  2. Press down and rotate the nozzle body to start threading.
  3. Tighten until fully seated.

Step 5: Final Lubrication of the Barrel

  1. Apply lubricant between the barrel and the shaper, focusing on the O-ring that seals this area.
  2. With the nozzle bumper down, rotate the shaper back and forth to work the lubricant in. Keeping it in this position for a few moments will allow the lubricant to drawn downward.

Done

Routine lubrication as needed can help keep your 1250 body Masterstream nozzle operating at peak performance. 

Still having issues? Contact our service team or find more service videos in our Learning Hub!