Silicone Dot 5 Brake Fluid

Bursonaw

Senior Member
I figured that it was time to rebuild the master and wheel cylinders for my 1941 Ford. The last time I could remember doing it was sometime around 1990. After 27 years of use I was very surprised to find that all the cylinders rubbers looked like the day I installed them, there was no pitting or rust inside any of the components. This is not meant to be a sales add for brake fluid, but it sure made a believer out of me.

Just thought I'd share my results.


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I figured that it was time to rebuild the master and wheel cylinders for my 1941 Ford. The last time I could remember doing it was sometime around 1990. After 27 years of use I was very surprised to find that all the cylinders rubbers looked like the day I installed them, there was no pitting or rust inside any of the components. This is not meant to be a sales add for brake fluid, but it sure made a believer out of me.

Just thought I'd share my results.


Sent from my iPad using Tapatalk

Thanks for sharing !
That is exactly why I installed dot 5 in my recent conversion from mechanicals to Lincoln hydraulics. Research and help / ideas from guys here convinced me that silicone fluid is 'non-hydroscopic' (?). If no water gets in, no rust should form. Your 27 year experience is pretty good proof that that is the case :) !
 
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Anybody know the best method for "flushing" all the Dot 3 fluid out of an existing brake system before using Dot 5?
 
Anybody know the best method for "flushing" all the Dot 3 fluid out of an existing brake system before using Dot 5?

I doubt that you will ever get all the Dot 3 out of your system. You can flush the lines, but getting all of it out of used cylinders and master cylinder may be a futile effort. Make the change when you are ready to rebuild or replace all the cylinders.
 
I filled the master cylinder with DOT 5 and then bled the system until it flushed out. No problems. Many moons since.
 
I replaced the master cylinder, wheel cylinders, and rubber lines. But before I installed all the new parts I flushed the hard lines with acetone than alcohol.
 
I replaced the master cylinder, wheel cylinders, and rubber lines. But before I installed all the new parts I flushed the hard lines with acetone than alcohol.

Hey Bill,
Sounds work intensive and maybe work. So, let us know if that works :) !
Hm, how will you know...no eventual rust in system in years to come ?

Hey Frank,
That's why the (?) mark added next to hydroscopic.
Thanks for the 'assist' ;)
 
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