^^^^^
I believe the above remedy is possible, but from a plumbing contractor point of view, my responsibility is to provide a reliable, working product without the hint of considering a cheaper/inexpensive fix at the mercy of the property owner.
I believe that a factory seal will supercede the best implied warranty coming from Zoeller pump company themselves, long before a plumber would even get the chance to sit in a courtroom and tell their side of the story how they saved the customer only $100 in replacing the switch over the entire unit without an implied warranty, and that's the reason the basement flooded and did thousands in damage.
It'll never go to court... the insurance company of the property owner will pay the bill and just collect off my insurance.
I cannot takes risks like the above, but if any property owner wants to do that, I respect that knowing the chances they take. One instant the seal is leaking in that equation of the cap, it's going to be a moment of memorable proportions as the pump will fail, and the cost of a new one looks very reasonable at that point.
I don't take gambles with my customers and their personal property in the risk of liability and damage.
I'm also the guy who comes in after someone has taken 'those' chances and found out the reasonable difference.