How to Repair a KMT Style On/Off Valve Using Kit #12967

Always make sure all high-pressure water has been removed from the valve by the following machine manufacturers' safety instructions. Failure to do so can cause severe injury or death.

Turn OFF all water pressure to the on/off valve.

Turn the on/off valve ON to raise the valve stem from the seat.

The valve components can be replaced with the valve body mounted to the table.

Loosen the high-pressure gland fitting using a 1-1/4" wrench.

Turn the air to the actuator OFF at the controls.

Disconnect the air line from the actuator.

Unthread the actuator from the valve body.

Remove all the valve components from the valve body with the included dowel.

Thoroughly clean the interior of the valve body with isopropyl alcohol or a similar cleaning agent before replacing the components.

Visually inspect the top and bottom of the valve bore for cracks/blemishes. If excessive wear or cracks are visible, replace the valve body.

Slide the O-ring on to the point of the valve stem.

Slide the stainleass steel back-up ring on to the valve stem point with the chamfer side towards the O-ring.

Slide the brass back-up ring on to the valve stem point with the chamfer side away from the stainless steel back-up ring.

Put the hoop on the high-pressure seal with the sharp edge of the hoop towards the seal.

Slide the hoop and the high-pressure valve seal onto the valve stem with the hoop towards the brass back-up ring.

Apply high-pressure lubricant to the outside diameter of the high-pressure valve seal.

Put the point of the valve stem into the valve body.

Push the valve stem with the dowel until it bottoms out.

Apply Blue Goop to the actuator threads.

Thread (hand tighten) the actuator into the top of the valve body until it bottoms out.

Reconnect the air line to the top of the actuator.

Turn the air to the actuator ON.

Apply Blue Goop to all surfaces of the seat.

Put the seat into the bottom of the valve body.

Clean the valve nut threads and the top of the nozzle tube of all Blue Goop.

Reapply Blue Goop to the threads of the high-pressure gland fitting and to the top of the nozzle tube.

Thread the high-pressure gland fitting into the bottom of the valve body.

Tighten the high-pressure gland fitting using a 1-1/4" wrench.

Turn the air to the actuator OFF at the controls.

Apply water pressure to the valve assembly to verify there are no leaks.

Quickly cycle the valve on and off a few times to purge the system of all contaminants before installing the cutting head.

Re-install the cutting head and continue the cutting process.