One Spring several years ago I found the toilet valve (the 'blade') on my van's Thetford Campa-Potti toilet to be stuck. I believe it was due to the rubber seal at the base of the toilet bowl adhering itself to the blade.
It was surprisingly tight and I don't quite remember what I used to get it loose -- silicone spray and steady pressure, perhaps. But I do remember learning that Thetford has a toilet seal lubricant and conditioner product. And that olive oil can be used as a substitute... at least according to several forum posts I found at the time.
Ever since that happened, I've occasionally put a few drops of olive oil on the blades of the toilets in my van and Hawk. I typically do that at the beginning and end of the season and when I can tell it needs it, i.e., when the blade doesn't move easily after the blade and seal have been cleaned. Even if it seems to slide pretty well, the olive oil makes it slide noticeably better. The olive oil has worked well and I've found no issues with it in hot or cold weather. You would think the olive oil would simply get scraped off when the blade is opened and closed a few times but that's not the case.
I noticed the manual doesn't say anything about using a lubricant/conditioner in the maintenance section so I called Thetford customer service this morning. The agent told me it's optional but also important to do if harsh cleaning chemicals are used to clean the bowl as those can deteriorate the rubber of the seal.
He had no objection to the olive oil and reiterated the manual's warnings against petroleum-containing products (like Vaseline) and vegetable-based oils. He also said it's ok to use silicone plumber's grease.
Having said that, I ordered a bottle of the Thetford Toilet Seal Lubricant and Conditioner product today. I guess it's worth $8 to me to see how it compares to the olive oil.
PS- I was also happy to learn that even though the manual doesn't say it, the seal can be replaced. He gave me part number 07101. I see they're about $10 on Amazon and reviews say it's easy to get the old one out and the new one in.
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