number line
Dot-3
Dot-4
&
Dot-5.1
These brake fluids are all a little better than the last.
Dot-5.1 has been called "the Super Dot-4."
Better heat control
Higher boiling temperature
Less water absorbent
They say don't mix them so, you are told to do a total replacement.
Don't get anal about it, I never did.
Now, Dot-5 is pure Silicone.
Doctors used this stuff for Breast implants.
Dot-5 Keeps your brake system clean, and rust free.
It will not absorb water.
If it will boil; I have never seen it.
Even when it drips on a hot header it still dose not flair up.
Dot-5 is the best!
Never mix this stuff with the other Dots.
I just run it through the brake system by the bleeder valves at the wheels.
When it comes out purple, I stop.
Now, this is where I get a little anal about it.
I bleed all four wheels, and then I do it again!
If you get a spongy peddle, you need to do another bleeding.
I suggest you wait about two weeks so the fluids totally separate.
First remove the Fluid from the master cylinder, and then flush it through the bleeders.
The price of Dot-5 went up so high I find myself using Dot-3 again.
If Dot-3 turns black, go to Dot-5.1.
If Dot-5-1 Dose not fix the problem, go to Dot-5.
So if you run a race car, or go through lots of deep water crossings, or do a lot of steep hills, Dot-5 is the best tool for the job.
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Vent Bellows ???
I have no ideal if the high pressure of the brake system will destroy your bellows. It seems to me that the bellows was never intended for brakes. If it reduces the pressure in the brake lines, your brakes will suffer.
Honestly if I were to test such an item for my brakes, I would test it on a small car, and not a big heavy Deuce.