Polymers in brake fluid?

Status
Not open for further replies.
Joined
Mar 10, 2013
Messages
2,355
Location
NY
Hello, I was on walmart's website looking at brake fluid when i ran across this review http://www.walmart.com/ip/Super-Tech-DOT-3-Brake-Fluid-32-oz/16821254. I am wondering how import polymers in brake fluid are and how can you tell by looking at a data sheet to see if there are any in the brake fluid? I need brake fluid for my chevy k20 and was just concerned about how the brake fluid would affect the rubber in the master cylinder. I wouldn't want the seals to dry out or anything. The super tech brake fluid is appealing because of its low price. Thanks
 
I would be more concerned about getting old,contaminated fluid out of the system than the brand of the new fluid. Put in what is recommended and forget about it till the next brake job.
 
WalMart's Super Tech and Advance Auto's WearEver Brake Fluids are all I've used in the last 25 years, I have used these brake fluids in the vehicles in my signature and vehicles that I have before BITOG. They're fine!
smile.gif
 
I just went to Wal Mart looking for bake fluid to add to my 2003 Saturn. Much to my surprise, in very fine print on the back of the SuperTech bottle, it said that the fluid was to be used for top off only and was NOT to be used to replace the brake fluid in the system! Needless to say, I went with the Prestone after reading this. What ever could they have in that stuff that makes it unsatisfactory for a fluid replacement?
 
Now you have me curious. I'll have to take a look at the Canadian stuff and see if there's wording like that. In any event, last time I needed DOT 4, I went with Prestone, and Valvoline for DOT 3.
 
Originally Posted By: Boomer
I just went to Wal Mart looking for bake fluid to add to my 2003 Saturn. Much to my surprise, in very fine print on the back of the SuperTech bottle, it said that the fluid was to be used for top off only and was NOT to be used to replace the brake fluid in the system! Needless to say, I went with the Prestone after reading this. What ever could they have in that stuff that makes it unsatisfactory for a fluid replacement?


That is very strange considering right on the bottle it says it meets all DOT 3 specs.
 
Originally Posted By: Nate1979
Originally Posted By: Boomer
I just went to Wal Mart looking for bake fluid to add to my 2003 Saturn. Much to my surprise, in very fine print on the back of the SuperTech bottle, it said that the fluid was to be used for top off only and was NOT to be used to replace the brake fluid in the system! Needless to say, I went with the Prestone after reading this. What ever could they have in that stuff that makes it unsatisfactory for a fluid replacement?


That is very strange considering right on the bottle it says it meets all DOT 3 specs.


Sounds like attorney weasel words. A plausible deniability way to avoid liability, in the case of any sort of brake failure lawsuit. Or......It might just be me.
 
Originally Posted By: joegreen
Hello, I was on walmart's website looking at brake fluid when i ran across this review http://www.walmart.com/ip/Super-Tech-DOT-3-Brake-Fluid-32-oz/16821254. I am wondering how import polymers in brake fluid are and how can you tell by looking at a data sheet to see if there are any in the brake fluid? I need brake fluid for my chevy k20 and was just concerned about how the brake fluid would affect the rubber in the master cylinder. I wouldn't want the seals to dry out or anything. The super tech brake fluid is appealing because of its low price. Thanks


The comment came from some uniformed individual who does not appear to have any knowledge of even basic chemistry. He probably is upset because he had to pay for it after they discovered he was walking around with it in his pants.

Toyota had a number of brake problems which resulted in recalls. The brake system supplier put O-rings and other component in there there not compatible with the common brake fluids.

All you have to do is google:

https://www.google.com/webhp?sourceid=ch...a+Brake+Recalls

Quote:
Chemistry of Brake FLuids
by Permission of Author (Molekule)

A brake fluid is first and foremost a specialized hydraulic fluid. A hydraulic fluid transmits power from one point in a vehicle (pedal/vacuum boost unit) to another (brake calipers). Hydraulic fluids used in automotive hydraulic brake systems must satisfy a variety of requirements.

In manual trasmission equipped cars, this same type of fluid may transmit power from the clutch pedal’s hydraulic cylinder to the clutch actuator cylinder to activate the throw-out bearing, for clutch disengagement during gear changes.

In general, the requirements for a brake fluid include chemical and thermal stability, suitable viscosities for the intended use, fluidity over the use-temperature range, low volatility, non-corrosiveness to metals, limited effect on rubber parts and good tolerance for water. Thus, a hydraulic brake fluid to be commercially acceptable is required to meet industry-accepted specifications as well as those established by governmental agencies. Industrial specifications include Society of Automotive Engineers (SAE) specifications such as 7Or1 Artic and 7Or3. Governmental specifications include National Highway Traffic Safety Administration, Department of Transportation, Federal Motor Vehicle Safety Standard 571.116 and 571.116a.

Automotive hydraulic brake fluids used today are most often synthetic glycol-base, water-miscible fluids. Brake fluids generally have been blends of several components such as vegetable oils, various alcohol-based fluids, synthetic ester base oils, diluents and one or more oxidation and corrosion inhibitors. Blended hydraulic fluids have contained such lubricants as castor oil, polyoxyalkylene glycols, glycol ricinoleate, and glyceryl ethers of polyoxyalkylene glycols and such diluents as butyl alcohols, amyl alcohols, glycol esters, polyoxyalkylene glycols, monobutyl ethers, ethylene glycol monoalkyl ethers and the like.

In addition to the myriad of synthetic base fluids (they can range from 7 to 11), brake fluids have anti-oxidants, corrosion inhibitors, and metal deactivators included.

Not all blends have been entirely satisfactory in all cases. Those that are satisfactory with respect to most of the requirements are difficult to prepare, since a blend component that satisfies one requirement may be disadvantageous with respect to another requirement. Thus, a blend component that meets a high boiling point requirement frequently does not meet the low temperature viscosity requirement or a blend component that satisfies the low temperature viscosity requirement may adversely affect rubber parts used in hydraulic systems, e.g., cause swelling, softening, and the like.

Brake fluid absorbs moisture form the atmosphere, thus it is hygroscopic. Moisture gradually reduces the boiling point, so the fluid should be changed periodically to remove water and other contaminants and to ensure the continued effectiveness of the braking system.

The properties of different types of brake fluids are tested for many different characteristics such as ph value, viscosity, resistance to oxidation, and stability, and graded against compliance standards set by the United States Department of Transportation (DOT) as noted above.
Brake fluid DOT specifications:

DOT 2 is castor oil based; pretty much obsolete.
DOT 3 is composed of various glycol esters and ethers.
Boiling point: 284° F (140° C)
DOT 4 is also composed of glycol esters and ethers, and boronic compounds.
Boiling point: 311° F (155° C)
DOT 5 is silicone-based. It is NOT recommended for any vehicle equipped with antilock brakes (ABS). It gives better protection against corrosion, and is more suitable for use in wet driving conditions.
Boiling point: 356° F (180° C)
DOT 5.1 is a high-boiling point fluid that is suitable for ABS-equipped vehicles. It contains polyalkylene glycol ether, but is more expensive than other brake fluids.
Boiling point: 375° F (190.6° C)
Even if they have similar base composition, fluids with different DOT ratings must NOT be mixed.


http://www.bobistheoilguy.com/forums/ubb...ids#Post3076040
 
Last edited:
Status
Not open for further replies.
Back
Top