Replacement Actuated RV Waste Valve for a Black Tank on a 2020 Grand Design 390RK
Updated 07/03/2026 | Published 06/28/2026
Products Featured in This Question
Question:
I have a 2020 Grand Design 390RK. Ill be replacing the black dump valve and cable assembly. The specs say my unit has the 66N4BB72GM which is the spigot to spigot 3inch valve with a 72inch cable. I dont plan on replacing the spigot ends because they are glued in and fine from the factory. I will essentially just be replacing the valve body/actuator and cable assembly. Do they offer just the valve body for this case? I imagine most people dont need to cut off their valves since they come apart. The spigot or hub ends are not typically replaced unless a person cracks a pipe. My cable is broken and the valve doesnt seal internally anymore. That is why I just need the valve.
asked by: Ryan R
Expert Reply:
Welcome back Ryan and thanks for the information. The LaSalle Bristol Cable-Actuated RV Waste Valve item # 34466N4BB72GM is going to be the correct one for your 2020 Grand Design 390RK. Unfortunately, the valve body can not be purchased separately.
The good news is you won't need to cut off the ends that slide into your sewer pipes. You'll simply be able to unbolt the broken valve body and then bolt the new one right back in. The item # 34466N4BB72GM is an exact replacement for the one that came on your Grand Design so the bolts will line right up.
If you have any additional questions, go ahead and click on the box that says Add Comment and I'll be happy to answer them.
(click to enlarge)
John A.
7/3/2026
The hardest part was getting into the valves and getting your bolts out and putting them back in , other than that it’s plug-in play
Product Page this Question was Asked From
LaSalle Bristol Cable-Actuated RV Waste Valve - Black Water Tank - Spigot to Spigot - 72" Cable
- RV Waste Valves
- Straight Valve
- Single Waste Valve
- 3 Inch Valve Body
- 72 Inch Cable
- Cable-Actuated
- 3 Inch Spigot
- Stationary Valve
- LaSalle Bristol
more information >
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on RV Waste Valves
Doug S.
7/3/2026
Ryan, I have replaced both valves (black & grey). It was fairly straight forward. My biggest obstacles were my big hands in a tight space and cutting the plastic board casing that hid the plumbing under my Winnebago trailer. (And, closing it back up well enough that I wouldn’t lose it rolling down the highway.) All works well now. I do suggest to double check the gasket seal and to use lubricant to avoid leaks with a clean tank??. I am sure I saved myself a few hundred dollars in labor. Total for 1 valve was about an hour for me. Good luck!