Join Date: Feb 2007
Location: Spain + Germany
My Motorhome: Four Winds RV
Thanked 632 Times in 588 Posts
A few photographs would help us see the problem.
It does sound as though you are talking about a cable operated waste valve. If so there are videos on YouTube showing how they come apart because many American motorhomes have cable operated valves.
Brexiters. It's your sh1t now. Whatever happens nationally and internationally you own it. I wish you luck. I think you're going to need all you can get and then some. Friday 13th December 2019.