Silicone Fluid

[Thomas C]

I saw the messages below that said you had to completely drain and flush the current fluid out of the system. What would happen if I drained the system and added silicone fluid (I don't really want to tear apart master cylinder and calipers). Thanks in advance.

tom

[James F.]

Re: Silicone Fluid

Tom, You won't be happy with the results if you don't have every molecule of Dot 3/4 out before you replace it with Dot 5 (silicon). New lines (or really well flushed out lines) and rebuilt master and brake cylinders are the "easiest" way to go in the long run. Regards,

[James F.]

Re: Silicone Fluid

Tom, You won't be happy with the results if you don't have every molecule of Dot 3/4 out before you replace it with Dot 5 (silicon). New lines (or really well flushed out lines) and rebuilt master and brake cylinders are the "easiest" way to go in the long run. Regards,

[Joe L.]

Re: Silicone Fluid

Thomas----

I totally agree with Jim Frakes comments. Bear in mind that at one point in time, DOT 5 silicone fluid was "heralded" by brake fluid manufacturers as being "compatible" with DOT 3 and 4 glycol-based fluids. They now seem to have mostly backed off that claim and, generally, recommend complete removal of the glycol fluid prior to installation of the silicone type.

Silicone fluid and glycol-based fluids are not compatible or miscible. This means that when there exist the two types of fluid in a brake system, they do not mix, but, rather, exist as seperate "entities" and are "phase seperated". The glycol fluid occupies its space and the silicone occupies its space. That means that all of the negatives associated with glycol fluid remain---it absorbs water, biologically and chemically degrades, and corrodes brake system metal components as a result thereof. In addition, since no chain is ever stronger than its weakest link, the benefits of silicone are not realized since there still exists the glycol in the system.

I have also been told, but never personally confirmed, that after a period of time with the 2 different fluids in the system, a sort of "gelatinization" occurs which increases the "viscosity" of the fluid.

[Joe L.]

Re: Silicone Fluid

Thomas----

I totally agree with Jim Frakes comments. Bear in mind that at one point in time, DOT 5 silicone fluid was "heralded" by brake fluid manufacturers as being "compatible" with DOT 3 and 4 glycol-based fluids. They now seem to have mostly backed off that claim and, generally, recommend complete removal of the glycol fluid prior to installation of the silicone type.

Silicone fluid and glycol-based fluids are not compatible or miscible. This means that when there exist the two types of fluid in a brake system, they do not mix, but, rather, exist as seperate "entities" and are "phase seperated". The glycol fluid occupies its space and the silicone occupies its space. That means that all of the negatives associated with glycol fluid remain---it absorbs water, biologically and chemically degrades, and corrodes brake system metal components as a result thereof. In addition, since no chain is ever stronger than its weakest link, the benefits of silicone are not realized since there still exists the glycol in the system.

I have also been told, but never personally confirmed, that after a period of time with the 2 different fluids in the system, a sort of "gelatinization" occurs which increases the "viscosity" of the fluid.