With DOT 3 or 4, it absorbs moisture out of the air. If you check your fluid now in any car it will be brown or black. This indicates it is horribly saturated with water. This is why all car makers tell you to purge the system every 2 years.
I hate bleeding the brakes, so I converted 2 of my cars to DOT 5 silicone fluid. One was 12 years ago, the other over 4 years ago. The fluid in both is still perfectly clear.
The only downside is that you technically have to dissassemble all your brake cylinders and wash off all traces of the old DOT 3 fluid because the two fluids are not compatible. I didn't do that, instead, I flushed methanol through the components and dried them out with compressed air. Repeat 3-5 times.
I did a test once by pouring some DOT 3 into some silicone fluid. They were like oil and water.
The naysayers will say VW components are not compatible with DOT 5. In 12 years I think I would have seen a problem.
The pedal is slightly spongy, but so what? Hit the brakes, the car stops. What else needs to happen? Not one person that has driven my car has noticed the difference. Hit the brakes, the car stops.
Don't get your DOT 5 fluid from Lordco, get it from CDN Tire. The 500ml bottle at CDN Tire is about half the price of the 375ml bottle at Lordco. I found that the fluid that came out of the system was so clean (and since it doesn't absorb water...) that I just recycled it back into the MC on the initial bleeding. Once the system was air free, I bled through virgin juice. This kept the cost down.
I don't think the boiling point of the fluid you use is relavent on the street. You will never use your brakes repeatedly enough to come even close to causing the fluid to boil. At the most you might do one hard brake from high speed every few days, then you'll drive slowly. It's not like a race track where you haul the car down from high speed at the end of the straight on every lap.
