Saving Lives & Protecting Property
Summary: If a Metro 1 fixed gallonage nozzle starts sliding instead of twisting, leaks from under the shaper, or seeps around the coupling, the usual fix is in the front end of the nozzle. Doug Heller walks through how to service the shaper, replace damaged Torlon guide balls and worn O-rings, clean and lubricate the barrel cone and grooves, and reassemble the coupling correctly. The big keys are keeping track of the ball bearings, cleaning threads before applying Loctite, using a light coat of silicone grease, and completing the proper flow test before putting the nozzle back in service.
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This service procedure is aimed at firefighters and maintenance personnel working on a break-apart Metro 1 fixed gallonage nozzle with an F140 ball shutoff valve. According to Doug Heller, the most common issues show up in a few ways: the shaper starts sliding back and forth instead of twisting, the front end takes an impact and damages the shaper guide balls, water leaks from underneath the shaper back toward the operator, or leakage develops around the coupling.
If that sounds familiar, this front-end teardown is designed to solve those problems without disturbing parts that do not need to move.
Doug makes one point early that is worth repeating: avoid changing the position of the fixed shaft if at all possible. That shaft holds the baffle and flow disc, and its setting determines the nozzle’s overall flow. If the shaft is not damaged, leaving it alone makes the service work much simpler and helps avoid unnecessary recalibration later.
For front-end service on the Metro 1 nozzle, Doug calls for a short but specific tool list.
The video also notes an expected service time of about 30 to 60 minutes.
If the nozzle shaper slides straight back and forth instead of rotating normally from straight stream to fog, the usual cause is damaged Torlon guide balls inside the shaper assembly. Doug describes these as sacrificial parts. If the nozzle takes a hard front-end hit, those three small balls are designed to fail before the more expensive aluminum parts do.
That means a nozzle that slides instead of twists is usually telling you exactly where to start.
To separate the shaper from the shaper guide, Doug uses a shaper guide clamp fixture in a vise and a long strap wrench on the shaper. The threaded joint between those parts is secured with red Loctite, so it may take some force to break loose. In stubborn cases, he notes that heat may be required, with care taken to protect the rubber bumper.
Once that joint is loose, stand the nozzle upright before pulling the barrel and nozzle assembly out of the shaper. That matters because there are not just three Torlon balls in the assembly. There are also many tiny white nylon ball bearings inside the shaper. Keeping the nozzle upright gives those bearings a better chance of staying where they belong instead of bouncing across the bench.
The white nylon balls ride against the barrel cone and help keep the shaper centered on the nozzle. They also help pull the barrel cone back when the nozzle is moved into full flush.
There is also an O-ring inside the shaper that creates the water seal between the shaper and the barrel cone. If water sprays back at the operator from underneath the shaper guide, that O-ring is likely worn or damaged. Doug also points out a second clue: if the shaper feels floppy and spins too easily, that same O-ring may be worn out.
To fully access the Torlon guide balls, the shaper guide has to come off the nozzle. That means removing the coupling first.
The coupling is retained by a set screw with blue Loctite and held in place by 34 stainless steel 1/8" ball bearings. Once the set screw is removed, those ball bearings can be dumped out and the coupling removed. With the coupling off, the shaper guide can come off completely, allowing access to the three Torlon balls and the grooves they ride in.
If the nozzle had sheared balls, all debris should be picked out and cleaned away before reassembly.
If leakage is showing up between the coupling and the barrel of the nozzle, Doug says to inspect the coupling O-ring. On the Metro 1 shown in the video, that is a number 134 O-ring. This is also a good time to replace the standard 1.5" hose gasket in the coupling.
No grease is needed on the hose gasket, but the O-ring sealing surfaces do need to be lubricated correctly during reassembly.
This is one of the easiest details to skip and one of the most likely to cause trouble later. Doug stresses the need to clean greasy threads with acetone before reapplying Loctite. That applies both to the shaper threads and to threaded areas where set screws will be reinstalled.
If the threads are oily or greasy, the Loctite may not set up the way it should.
Before reassembly, check that the barrel cone moves freely and springs back on its own. This is the part that pulls back for flush. If it does not move freely, Doug recommends spraying Break-Free CLP around the backside to free it up.
He also makes clear that the barrel and barrel cone are not really field-serviceable internal components. If lubrication does not free them up, that assembly would need replacement.
Once everything is cleaned up, apply a light coat of 100% silicone grease to the helical grooves and the barrel cone. A little goes a long way here. The shaper can then be slid back onto the nozzle, positioned about midway between straight stream and fog.
Next, the shaper guide goes on with the threads facing the shaper. At that stage, the three Torlon balls are dropped into their holes and held in place while red Loctite is applied around the threads. Doug notes that one of the hardest parts of the whole job is getting those balls in, keeping them in place, and getting the threaded joint started without pushing them out.
Once aligned, thread the shaper onto the shaper guide and tighten it until it bottoms out. After that, the red Loctite needs time to set up. Doug recommends giving it a couple of hours before returning the nozzle to service.
Before installing the coupling, put grease on the O-ring sealing surface at the back of the nozzle and in the ball bearing groove. Then install the O-ring on the nozzle itself, not inside the coupling. Apply a light coat of grease over the full circumference of that O-ring and also grease the inside of the coupling.
When pushing the coupling back on, do it squarely and firmly. You should feel it pop over the O-ring. If the O-ring starts to roll, stop and start over. A rolled or pinched O-ring can create a leak.
Doug also points out that this is a lockout coupling, not a swivel. The set screw hole must line up with the machined pocket in the nozzle when the coupling goes back on.
The coupling is retained by 34 stainless steel ball bearings. In field service, those usually have to go in one at a time. Doug shows a faster in-shop method, but the key point is the same either way: all ball bearings need to be installed correctly before the set screw is tightened.
Once the bearings are in place, apply blue Loctite to the set screw and tighten it into the machined pocket until it is snug. It does not need to be cranked down hard. It just needs to bottom out properly in the pocket so the coupling stays locked in place.
Doug closes with one shop rule that should not be skipped: after any service work, complete the prescribed flow test for the fixed gallonage nozzle you worked on. Reassembly is not the end of the job. The nozzle needs to be tested before it goes back into service.