Servicing & Replacing RV Waste Valves
RV waste holding tank gate valves (typically 3-inch for black tanks and 1.5-inch or 2-inch for grey tanks) use a sliding plastic paddle sandwiched between two grooved rubber seals. Over time, tissue buildup, dried debris, and hard water scale cause the handles to pull hard or leak liquid past the cap.
Replacing Gate Valve Assemblies and Seals
- Ensure both holding tanks are completely drained and flushed clean before starting work.
- Remove the 4 corner bolts and nuts holding the valve body sandwiched between the two pipe flanges.
- Carefully spread the plumbing flanges apart and slide out the old valve body and rubber seals.
- Clean all debris, rust, and scale off the flat inner faces of the pipe flanges.
- Coat the dual seals of a new 3-inch Valterra waste valve or replacement kit with a thin layer of plumber's silicone grease to hold them in place against the valve body grooves during insertion.
- Slide the new valve assembly between the pipe flanges, taking care not to pinch or roll the rubber seals out of their seat grooves.
- Re-insert the 4 corner bolts and tighten nuts evenly in a cross pattern (do not overtighten to avoid cracking the plastic housing).
If you experience occasional cap drips from a aging valve assembly, installing a twist-on auxiliary waste valve onto the end of your sewer bayonet outlet provides a secondary seal and keeps your hands dry when removing the cap.
See also: