DOT5 or DOT3? That is the question.....
I would agree about the DOT5 fluid and the idea of changing over to DOT3.
I would guess (and this is pure speculation on my part) that the corrosion comes when the system becomes empty and then air/moisture can enter into it. It probably does not help that a lot of trucks, especially deuces, that were bad ordered were simply parked for years before being sold to us and this appears to be the case with my truck.
The longer a truck sits without proper fluids out in the weather the worse the internal damage is to the wheel cylinders and master cylinder as well as the airpack.
Suffice it to say, if it becomes necessary to completely flush out my brake system, I will be very tempted to convert over to DOT3. For now, as long as things work as they should, I am keeping the DOT5 in the system. In the interest of avoiding a fire hazard, I am changing over to the air switch for my brake lights as DOT5 has a nasty habit of burining if your brake light switch has a short. I saw this happen a week ago at the MTA show after it had closed on a M109 that had been parked with the lights left on. Fortunately there were many people there who recognized what was happening and saved the truck from any damage other than some lost fluid and a new switch.
Just my nickels worth (Used to be 2 cents, but with inflation....)
RL