Ive heard the same about dot 5, eating into the rubber components that were not made for it. I was really surprised when I bought a few new wheel cylinders for my COE and they were rated for either dot 3 or 5. I havent seen that before on older replacement parts.
Typically you might have one component in the system that is not compatible, such as an old hydrovac, and as such, I wouldnt go that route. If you have any question about dot 5, do not use it.
Another thing Ive heard happen is that if your brake booster gets screwed up internally, it can suck fluid into the engine due to the vaccum used to activate it. Dot 3 burns, dot 5 burns leaving sand. Not good in any engine.
There are two things you dont screw around with, brakes and steering. So if theres any question about it, walk away.
Jeff
