ruggedharbor77 said:Man, I don't know why you're overthinking this...
God forbid you end up without brakes just because of something as minor as changing the oil for your $33.🤷
I'll probably swap the oil during the Black Friday sales, mostly because my old bike is going up for sale soon and I want to service it first... it's pretty filthy and greasy 😁 ..
And about the "overthinking" part... I really don't think I am. Because regarding mineral oils, what you're saying just isn't right—unless we're all just blindly following Wikipedia 😉 ..
Here's the link, and the important part from the Wiki:
"Most automotive professionals agree that glycol based brake fluid,
(DOT 3, DOT 4, DOT 5.1) should be flushed, or changed, every 1-2 years.[1] Many manufacturers also require periodic fluid changes to ensure reliability and safety. Once installed, moisture diffuses into the fluid through brake hoses and rubber seals and eventually the fluid will have to be replaced when the water content becomes too high. Electronic testers and test strips are commercially available to measure moisture content. The corrosion inhibitors also degrade over time. New fluid should always be stored in a sealed container to avoid moisture intrusion.
DOT 5 is silicone fluid and the above does not apply. Ideally, silicone fluid should be used only to fill non-ABS systems that have not been previously filled with glycol based fluid. Any system that has used glycol based fluid will contain moisture, glycol fluid disperses the moisture throughout the system and contains corrosion inhibitors. Silicone fluid does not allow moisture to enter the system, but does not disperse any that is already there either.
A system filled from dry with silicone fluid, does not require the fluid to be changed at intervals, only when the system has been disturbed for a component repair or renewal. The United States armed forces have standardised on silicone brake fluid since the 1990s."
http://en.wikipedia.org/wiki/Brake_fluidOh, and I found another interesting difference between mineral and DOT fluids
Shimano uses mineral oil, and besides the OEM stuff, you can use Magurin, and from what I hear, it works great for Citroen setups. I had amazing results using Magurin on my Shimano brakes, so give that a shot. Definitely stay away from DOT. Mineral oils have additives to swell the seals, but DOT doesn't. DOT is aggressive and eats through rubber that isn't a high-grade NBR designed to resist DOT fluids. Every brake system has seals designed specifically for the type of fluid it uses, so it makes sense why mixing them is a bad idea.