I know the valve seals on the dump valves are some type of rubber. What does anyone do to lube them to keep them from drying and cracking? That is if anyone does anything.
I have only had to replace them once. On my first TT, a 1975 Prowler that I bought around 93-94...They started leaking a year or two later. An easy job, and the parts are cheap. My next TT was purchased new in 2001. 10 years of use and the seals were fine.
I don't do anything to them. Doubt that there is anything that would extend the life enough to justify the cost/effort.