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Ron K.

Which Brake Fluid

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Okay Lincoln-Zephyr Drivers, I am in the middle of replacing the master cylinder, all wheel cylinders and the flex lines, what type of brake fluid do you experts use? I use silicone in most of my treasures but don't know if it is appropriate in this beauty.

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Ron;I was using Silicone fluid for about 20 Years. Always seemed to have a "Soft" pedal..They now sell A Synthetic Brake Fluid that has all the qualities of the silicone fluid , it's less expensive and does not draw moisture .. I switched to it about Four Years Ago,works fine and has a Good Solid Pedal .. Since Your system is clean or dry you might consider the Synthetic Fluid..

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Thanks for the response, I have been using that in my wife's car and did not know that it was better than silicone. Can you mix it with other fluids?

Ron

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They now sell A Synthetic Brake Fluid that has all the qualities of the silicone fluid , it's less expensive and does not draw moisture .

Not sure about this. I believe the term "synthetic" for brake fluid just has to do with the processing or rearranging of molecules of the fluid like with synthetic motor oil. Synthetic brake fluid is glycol based, compatible with all conventional brake fluids ( DOT 3, 4 and 5.1). Therefore it is hygroscopic and will absorb water.

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The Cabriolet will have a completely new/cleaned out system and I will use the "synthetic" fluid, I was just wondering about adding it to my other vehicles. I guess if all else fails, I could read the instructions on the container.

Ron

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PAUL K ;The Brake Fluid I was referring to is Valvoline Synthetic DOT 3&4 Brake Fluid ..I am not a Chemist, but It States a high dry boiling point of 480 deg. and contains a complex mixture of "Glycol Eithers","Polyglycols" and "Inhibitors"...In laymens terms , Glycol Either is A Solvent , Polyglycols are a Biogradable Base for synthetic lubricants and, Inhibitors (In this Use) are a Substance that decreases the rate of (or) stops completely a Chemical Reaction..Not sure where the "Water Absorbtion" comes into play here..Also not sure of the make-up of Regular brake fluid...

Edited by notnow (see edit history)

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PAUL K, I stand corrected.. I did a little Research and you are Correct . Regular and Synthetic Brake Fluid are Both Glycol Ether Based ..Regular Brake Fluid Is Not Petroleum Based...DOT 3,4 and 5.1 are all Glycol Ether Based...Also I found out that DOT 5 (Silicon Brake Fluid) should not be Used in Any ABS Brake System. (I Didn't Know That) ..I learn Something almost every Day..CH

Edited by notnow (see edit history)

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DOT 5 brake fluid is not recommended for ABS systems because the molecules are smaller and aerate more easily. This causes a soft pedal or reduced braking power when the ABS solenoids activate and cycle.

Synthetic brake fluids have additives as NotNow mentioned which "inhibit" the absorption of moisture. Castrol has had one for years which is their LMA product. If I remember the LMA stands for Low Moisture Absorption or Activity.

Also, although DOT 5 silicone fluid will not absorb moisture, that does not mean that air still does not enter the brake system. The moisture from the air that enters the brake system will not mix with the fluid, settle to the lowest point in the brake system and is often impossible to bleed out. This causes a pocket of water in the system and causes corrosion. That is why some systems corrode even with the use of silicone fluid. Nothing replaces routine brake fluid flushes for brake system longevity.

And Ron K. , so long as your other vehicle DO NOT have silicone brake fluid, you can top them off with the synthetic.

Edited by Paul K. (see edit history)

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If you have not replaced the brake lines, I would highly recommend that you do so. Moisture that got into the DOT 3 or 4 fluid that was used before could already have started to rust the lines from the inside out. On aeration of the DOT 5, DO NOT shake the can of fluid before you add it to the system. Since the DOT 5 aerates so easily, you will be inducing air into the system and thus a spongy pedal. Do not pump the pedal vigorously when bleeding the brakes as this can aerate the fluid also. I have used DOT 5 for over 20 years and never had a soft pedal.

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V12 Bill ; We do have a Difference of Opinion ..I use a Vacuum Pump when I bleed brakes, which makes the Job quite Easy !! Buy one and try it before YOU Offer Instructions ..There is some degree of Agitation just by adding Fluid to the Master Cylinder and Tilting the Container to do so ! Soft Pedal has always been a Problem for me even before I started using a Vacuum Pump..( I also have a Problem with another thing being Soft ,and they make a Vacuum Pump for it also ..But since I'm 77 years old, I'll Pass on that !) Any way You Have Your Opinion and I have Mine .. I'm Finished with this Subject, Have a good 2012 ...CH

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