Brake fluid

[ALLZS]

Running regular fluid in my car now is there a way to flush and install silicone type fluid can i just clean out the master cylinder and push the new through ?

[Mr. Chevy]

Yes, I did it on my cars... Empty your master cylinder of the old Dot 3, fill with silicone and push it through the system bleeding all four brakes until you see purple fluid, the silicone, and all the Dot 3 is washed out.

Not too bad to do just time consuming..

Rich

[67 Nova Boy]

Why do you want to run Silicone fluid? Dot 5

Dave
67 Nova Boy

[Mr. Chevy]

Dave, silicone is non corrosive, you can leave it in there for ever and not worry about moisture issues. Also if some accidentally spilled on a finish the silicone won't hurt anything, just wipe it off. Dot 3 is nasty stuff if it gets on something...

Rich

[parkbrau]

How about all the seals?

[67 Nova Boy]

Dave, silicone is non corrosive, you can leave it in there for ever and not worry about moisture issues. Also if some accidentally spilled on a finish the silicone won't hurt anything, just wipe it off. Dot 3 is nasty stuff if it gets on something...

Rich

Rich,
This was quoted from another forum that says it better then I can...


Of critical importance in determining a fluids ability to handle high temperature applications is the Dry Boiling Point and compressibility.


The Dry Boiling Point is the temperature at which a brake fluid will boil in its virgin non-contaminated state. The highest temperature Dry Boiling Point available in a DOT 3 fluid is 572° F.

The Wet Boiling Point is the temperature a brake fluid will boil after it has been fully saturated with moisture. The DOT 3 requirement for wet boiling point is a minimum temperature of 284° F.

There are many ways for moisture to enter your brake system. Condensation from regular use, washing the vehicle and humidity are the most common, with little hope of prevention. Glycol based DOT 3 & 4 fluids are hygroscopic; they absorb brake system moisture, and over time the boiling point is gradually reduced. Here is a scary statistic, a new car at 12 months old will have a 2% water content if never driven, at 18 months it will be 3% or higher depending on atmospheric conditions. It is not unusual to have 8-12% water content in the average automobile on the street.

You should not use DOT 5 fluid in any racing application for the following reasons. DOT 5 fluid is not hygroscopic, so as moisture enters the system, it is not absorbed by the fluid, and results in beads of moisture moving through the brake line, collecting in the calipers. It is not uncommon to have caliper temperatures exceed 200° F, and at 212° F, this collected moisture will boil causing vapor lock and system failure. Additionally, DOT 5 fluid is highly compressible due to aeration and foaming under normal braking conditions, providing a spongy brake feel. DOT 5 fluid is best suited for show car applications where its anti-corrosion and paint friendly characteristics are important.

Whenever you add fresh fluid to your existing system (never mix fluids of different DOT classifications), it immediately becomes contaminated, lowering the boiling point of the new fluid. For maximum performance, start with the highest Dry Boiling Point available, flush the system completely, and flush it regularly, especially after severe temperatures have been experienced.

If you happen to mix DOT 3/4 and DOT 5 you will end up with a coagulated gel that will seriously compromise your braking performance. Dot 5.1 is a Glycol based fluid like DOT 3 or 4 and should not be confused with DOT 5 which is silicone based, many new European cars specify DOT 5 but in Europe they don't recognize the silicone based (DOT 5) fluid so they really mean DOT 5.1, ensure you don't confuse the two. DOT 5.1 was developed for ABS braking systems and is of a thinner viscosity to allow shorter cycle timing, it's boiling point is similar to DOT 3 or 4.

[67 Nova Boy]

How about all the seals?

Another post to help all decide on what fluid to use and why.

http://www.chrysler300club.com/tech/fluid/brakefluid.html

Dave
67 Nova Boy

[Mr. Chevy]

Good info Dave thanks.

I have had silicone fluid in my 69 Chevelle and 70 Nova now for nearly 10 years and have never had any issues and I do drive both cars.

Rich

[67 Nova Boy]

Brakes are not something to play with...most every one on this site has a classic car and would not like to here about one getting into an accident due to brake issue.

Very glad to hear your doing good with the dot 5 fluid...keep up with your maintenance on your brake system.

Dave
67 Nova Boy

[Big Block Bill]

Excellent information Guys.

People think we are trying to up-sell them when recommending a brake fluid flush for their vehicle. Then later when the calipers lock up and need to be replaced, they complain about the expense. A very in-expensive service on any vehicle in the long run.

Bill

[ALLZS]

Thanks great info guys, is there any brand better that i should use

[SS427]

I have been using Dot 5 in all our restorations since 1981 and have NEVER heard of an issue from anyone. Keep in mind that most of these cars are not being daily or even multiple weekend driven cars and sit more than anything. For our daily driver restorations we use Dot 3. Our main reason for using it is for safety during the restoration as for the reasons mentioned earlier, it won't harm paint and is non corrosive. I don't care how careful you are, you WILL get brake fluid spillage someone sometime.

[L78steve]

Silicone fluid should never be used in collector cars, Period. Moisture will enter the system regardless of fluid type used.
Moisture will not mix with Silicone,It will mix with Alcohol based fluid.
When you flush out the alcohol base fluid the moisture goes with it.
This is why fluid must be changed every 2 years. Most manuals state this. Very important with anti lock modules.

[Burd]

I did Dot 5 in my 78 T/A. My mechanic reeommend it. He owns an all GM repair facility, Plus like said here, when you bleed the system, all the detailed painted parts don't get ruined. It works great. However, I replaced my lines and had everything rebuilt, only flushed out part was the prop valve.
The fluid in the back when I did it was nasty. Dot 5 is the way to go. I was just thinking, it's been 17 years already, time for a flush and refill.

[Burd]

I sent my OG master and calipers out, they only had 40 k on them but like mentioned, brakes are the most important thing on your car, I also sent my booster out to a guy in Portland, booster Dewy, he does awesome work, re-plated it as well. The whole price for all was $750. Pretty cheap, you gotta stop, lol

[McCune]

I am using Dot5 in my restoration. Glad to see others have done the same.

[scuncio]

I have also been using DOT5 for 20 years with no issues. Just flush and refill every few years to evacuate any trapped moisture.

[harry401]

DOT 5 in all my non ABS cars. Flush the calipers and rear cylinders every couple years like you should do on ALL brake systems anyways. All DOT 5 regardless of brand is manufactured by Dow