NEW BRAKES....DOT 5?
- Thread starter CFD244
- Start date
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I have been doing some thinking...
We know how bad that can turn out.
Dot 3,4,5.1 are hygroscopic, dot 5 is not.
Assuming there is no air in the system all of the surfaces are fully coated with dot 5 fluid.
Condensation occures where there is a junction between cold and less cold with moisture present. ( Here in CO the inside humidity is 30 percent, and when it gets below 20 deg out side I get frost on the inside of my house in places)
My gut says if I took a glass full of ice cold water and placed in into a container of either dot 3 or dot 5 there would not be any moisture buildup on the surface exposed to the fluid.
Now leave the containers of fluid open to a damp environment for a few months and redo the experiment. Then I would expect moisture to collect on the dot 3, but not on the dot 5.
My reasoning. There is nothing in the dot 5 pulling moisture into the fluid or container. The dot 3 is constantly pulling moisture from the air into the fluid.
If nothing is pulling moisture into the fluid, no moisture would be in the container or fluid.
Personally dot 5 is growing on me.
We know how bad that can turn out.
Dot 3,4,5.1 are hygroscopic, dot 5 is not.
Assuming there is no air in the system all of the surfaces are fully coated with dot 5 fluid.
Condensation occures where there is a junction between cold and less cold with moisture present. ( Here in CO the inside humidity is 30 percent, and when it gets below 20 deg out side I get frost on the inside of my house in places)
My gut says if I took a glass full of ice cold water and placed in into a container of either dot 3 or dot 5 there would not be any moisture buildup on the surface exposed to the fluid.
Now leave the containers of fluid open to a damp environment for a few months and redo the experiment. Then I would expect moisture to collect on the dot 3, but not on the dot 5.
My reasoning. There is nothing in the dot 5 pulling moisture into the fluid or container. The dot 3 is constantly pulling moisture from the air into the fluid.
If nothing is pulling moisture into the fluid, no moisture would be in the container or fluid.
Personally dot 5 is growing on me.
DrCharles
Well-Known Member
I run DOT 5 in my disc/drum system and it works great so far (years). I did find the hard way that it gets past the seals in my Howe clutch slave (pull) cylinder... rebuilt the slave, flushed the master and line, and now that master has DOT 4.
The urban legend that bad things will happen if you mix silicone and glycol fluids is still around, I see. NOTHING happens. No atomic fusion, no explosion, no "goop" formation. I have done it myself in a glass jar. They don't mix (the silicone floats on top the glycol) but there is absolutely no reaction. If you wait long enough, the purple dye in the silicone will migrate into the glycol. That's all. The fluids still don't mix. Can you imagine Dow Corning's liability if everyone's brake system blew up from accidentally or purposefully adding silicone fluid to one that had, or used to have, glycol?
The urban legend that bad things will happen if you mix silicone and glycol fluids is still around, I see. NOTHING happens. No atomic fusion, no explosion, no "goop" formation. I have done it myself in a glass jar. They don't mix (the silicone floats on top the glycol) but there is absolutely no reaction. If you wait long enough, the purple dye in the silicone will migrate into the glycol. That's all. The fluids still don't mix. Can you imagine Dow Corning's liability if everyone's brake system blew up from accidentally or purposefully adding silicone fluid to one that had, or used to have, glycol?
I'm not saying what you said is right or wrong. Only pointing out that chemicals behave differently hot and under pressure. What you observed may be correct at atmospheric pressure and room temperature.
Is it? Where in this thread? I missed it.
I read my bottle.of DOT 5 and states on the bottle to NOT mix with 3 or 4. I personally in our DOT 5 car have had ZERO issues.
I don't know, if you saw my post #2, I think I'm gonna try dunking my dong in DOT 3 and then redip in DOT 5. Looks like it might beat all those pills advertised for growth.
I own a restoration shop in the Midwest. I have converted dozens of my clients cars to DOT5 with NO issues. DOT3 is Hygroscopic & pulls moisture from the air. DOT5 repels moisture being silicone based. When DOT3 reaches it's saturation point the water settles out, mostly in the wheel cylinders with water being heavier.
If you have ever opened up a DOT3 seized wheel cylinder or caliper you will see the rust mostly at the lowest point. DOT5 doesn't have that problem...
I worked on a 64 Impala that was converted to DOT5, then shortly after was put in storage for 15 years before it came to my shop. The ONLY system I didn't have to rebuild were the brakes! Wheel cylinders, free, NO leaks & master cylinder was crystal clean! Like you filled it yesterday. I was already doing the 3 to 5 switch but THAT made me a true believer. I also worked on a concourse, trailered to car shows, 1955 T-Bird. The brake system was nothing but muck & rust & had been completely rebuilt about 10 years prior.
The reason DOT5 is NOT used in late model cars is that Silicone based fluids cannot tolerate the rapid pumping associated with ABS braking system.
DOT5 will "foam" when the pressure is cycled rapidly, DOT3 (or DOT4) does not.
If you have ever opened up a DOT3 seized wheel cylinder or caliper you will see the rust mostly at the lowest point. DOT5 doesn't have that problem...
I worked on a 64 Impala that was converted to DOT5, then shortly after was put in storage for 15 years before it came to my shop. The ONLY system I didn't have to rebuild were the brakes! Wheel cylinders, free, NO leaks & master cylinder was crystal clean! Like you filled it yesterday. I was already doing the 3 to 5 switch but THAT made me a true believer. I also worked on a concourse, trailered to car shows, 1955 T-Bird. The brake system was nothing but muck & rust & had been completely rebuilt about 10 years prior.
The reason DOT5 is NOT used in late model cars is that Silicone based fluids cannot tolerate the rapid pumping associated with ABS braking system.
DOT5 will "foam" when the pressure is cycled rapidly, DOT3 (or DOT4) does not.
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