Saving Lives & Protecting Property
Summary: If your ball shutoff valve is leaking through the waterway when closed, start with the rear seat—it’s a quick fix that often solves the problem without a full teardown. If you see leakage from the trunnion areas or continued bypass after replacing the seat, a full rebuild is required. Doug Heller walks through both approaches, including removing the coupling, servicing the ball and seats, reinstalling trunnions with proper Loctite and alignment, and drilling for new roll pins. The key details are keeping the ball aligned with a mandrel, cleaning threads before applying Loctite, and installing components in the correct orientation.
Need repair kits or parts? TFT provides rebuild kits and components for multiple ball valve series:
This service process applies to several TFT ball shutoff valve series, including F140, J140, F100, and D75. While the waterway sizes differ, the rebuild procedure is essentially the same across all models.
If your valve is leaking through the waterway when it’s shut off, start with the simplest solution: the rear valve seat.
These valves are designed with a quick-change rear seat that can be removed without tools. Open the valve slightly, remove the hose gasket, and pull the rear seat out with your finger. Replace it with a new seat and O-ring, reinstall the hose gasket, and tighten the hose connection to compress the seat against the ball.
In many cases, this alone will stop the leak.
If tightening the hose or replacing the rear seat doesn’t fix the issue, it’s time for a full rebuild.
If water is leaking from the trunnion areas on the side of the valve body, or if replacing the rear seat does not stop water from passing through the valve, a complete teardown is necessary.
This involves removing the handle, coupling, ball, and internal sealing components.
Start by removing the set screw from the coupling. Depending on the Loctite used, heat may be required to break it free.
Once removed, dump the ball bearings out over a container and remove the coupling. Inside, you’ll find an O-ring or quad ring that seals the coupling to the valve body. If leakage was present in this area, this seal should be replaced.
Use a flat punch to drive out the roll pins that connect the handle to the trunnions. Once the handle is disengaged, the trunnions can be unthreaded from the ball.
This is where the repair mandrel becomes important—it holds the ball in position so you’re not chasing it while trying to loosen the trunnions.
In most cases, the trunnions will need to be replaced rather than reused.
With the trunnions removed, the stainless steel ball can be taken out.
The ball typically does not need replacement unless it is severely scored or damaged. Clean it using Scotch-Brite to remove buildup from water deposits, rust, or debris.
Inside the valve body, remove the front seat and Belleville washer. These components apply pressure to keep the seat sealed against the ball.
Install the new Belleville washer first, with the crown facing the ball. Then install the new valve seat with the concave side facing the ball.
Before reassembly, thoroughly clean:
Any debris, corrosion, or buildup can prevent proper sealing.
Place the ball back into the valve body and insert the repair mandrel. This keeps the ball aligned with the waterway and ensures proper positioning for reassembly.
Apply a light coat of grease to the trunnion O-rings, but keep grease off the threads. If threads get contaminated, clean them with acetone before applying Loctite.
Apply red Loctite to the trunnion threads and install them into the ball. Tighten securely on both sides.
Position the handle so that when the valve is closed, the “OFF” marking is visible to the operator.
If using new components, the handle and trunnions will not be pre-drilled.
Use a No. 22 drill bit to drill through the handle and trunnions. Keep the drill perpendicular to ensure proper alignment. Once drilled, insert the roll pins and tap them into place until they are just below flush.
Apply grease to the O-ring groove and install the O-ring onto the valve body. Lightly grease the coupling’s internal surfaces.
Push the coupling straight onto the valve, then reinstall the ball bearings. This may need to be done one at a time in field conditions.
Reinstall the set screw with Loctite and tighten until just flush. Rotate the coupling to ensure it spins freely and does not catch on the ball bearings.
Install the rear seat with the concave side facing the ball and the flat side toward the hose connection. Apply a light coat of grease to the O-ring.
Finish by installing a new hose gasket in the coupling.
Some valves include a mounting point for a pistol grip. If adding one, ensure the correct spacer is used for the valve model. Without the spacer and washer, the mounting bolt can contact the ball and damage the valve.
Use a 5/16" ball-end Allen wrench to install the grip, apply red Loctite, and ensure the grip is oriented correctly before tightening.
If removing a pistol grip, replace it with the correct set screw and apply Loctite to seal the opening.
After reassembly, always perform a flow and pressure test to confirm proper operation. The valve should shut off cleanly, operate smoothly, and show no signs of leakage before being returned to service.