Have you noticed that no one on this post using DOT 5 has reported any problems with it? The one person reporting problems with leakage was using DOT 3.
Twenty five years ago I switched my '57 Belair to DOT 5. I didn't know anything about it except it didn't damage paint. I had a rear wheel cyclinder go bad. I rebuilt the wheel cyclinder, drained the fluid and refilled with DOT5. No replacing of the old rubber, no flushing the system, nothing. The brakes still work great.
A few years ago at a Classic Chevy convention, there was a seminar on brakes by one of the major brake manufacturing companies. When the guy finished his one hour presentation, he asked if there were any questions. I asked about DOT 5. He told all the urban legends about it harming rubber parts etc. When I asked about some verifaction, he had none. After further questioning, he told me that his company didn't make DOT 5.
That's because if they made DOT 5 they wouldn't sell nearly as many brake parts. I hear that Harley Davidson and Corvette use DOT 5. If it is good enough for them, it is good enough for me.
Found this on Mid America Auto Works website. "Certified DOT 5 Corvette Silicone Brake Fluid helps prevent corrosion because it does not absorb moisture. It also lubricates and preserves hoses and seals" (Did you catch the part about preserving rubber parts?)
wildbillscorvete.com says "The latest advances in brake fluids are the DOT 5 synthetic products. North American is a leading manufacturer, producing quart bottles of high quality silicone brake fluid. DOT 5 does not absorb moisture like the DOT 3 & 4 products available at the local parts store. This means that your system, particularly if it sits for long periods of time, will not corrode from lack of use. You don't need to start with a brand new system, a thorough bleeding of your existing system with silicone fluid will extend the life of your lines, calipers, wheel cylinders and master cylinder.
DOT 5 Silicone brake fluid is not some exotic chemical strictly for the professional racer, it can and is used in all systems except ABS... it simply is a better, high tech solution for your brake system.
Key Benefits
Non corrosive - doesn't absorb moisture
Protects brake lines, master cylinders and calipers
Won't deteriorate rubber seals and other parts (did you notice the part about Won't deteriorate rubber seals and other parts ?)
Lasts a lifetime
Won't harm painted surfaces if accidentally spilled"
I found this on harleyalaska.com "
DOT 5, is silicone based and does not absorb moisture and does not damage paint. DOT 5 should not be used in any vehicle with anti-lock brakes. The silicone based fluids tend to froth and cause tiny air bubbles when pumped excessively, thus the non use in anti-lock brakes. DOT 3& 4 are hydroscopic meaning they absorb moisture over a period of time. Moisture will cause corrosion in the master and slave cylinders in time if not flushed and replaced at proper recommended times or mileages. DOT 3 & 4 will eat your paint very quickly if left in contact with a painted surface. An open can of DOT 3 or will absorb moisture out of the air very rapidly"
So you decide. I'll stick with DOT 5. I will use it in all my cars until someone can prove to me that there is a problem with it.
