Vavoline Synth vs. Generic DOT 4 Brake Fluid

[Jim 5]

My car calls for DOT 4 fluid. I noticed valvoline has a "synthetic" brake fluid, and there are other brands high end fluid like ATE super blue etc.

What's the difference? I would have thought that even the generic or store brands have to meet some sort of DOT 4 Spec.

One other point. The valvoline brand says its ABS compatible. The generic stuff doesn't make that statement. I would guess that 90% of cars these days have ABS, and perhaps a higher percentage than that in the case of cars that require DOT 4. Am I correct to assume the generic stuff is ABS compatible unless it says otherwise?

Bottom line is, what's the difference between premium and generic DOT 4 brake fluid, and is the expensive stuff worth the price?

Thanks!

 

[Jim 5]

My apologies. I did a search and discovered that the better quality brake fluid has higher boiling points. The minimum boiling point for a DOT 4 appears to be 311 degrees. The better fluids can increase that by a very significant amount.

Anyhow, can anyone answer the remaining question about ABS compatibility?

Thx.

 

[labman]

The synthetic brake fluid is pure hype. All of it has always been polyglycol ethers. In the USA, most of the owners manuals call for DOT3 which is a little lower boiling. Despite being let down by Fram, I am still a sucker for brand names. I have been using Prestone DOT4, or at least their disk brake grade, for close to 40 years. Crap, they are now owned by Fram. For street use, likely any DOT4 is OK.

ABS systems were designed to work on DOT3. ABS compatible sounds like ** to me. The most likely way to get in trouble is to use old stuff that has set around in an opened bottle and drawn moisture. Pull your bleed screws out, clean them up, and put a good coat of Sil-Glyde or other silicone grease on them. They twist off much easier than solving that problem. See http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=24;t=000035#000000 before you bust it.

 

[Ken2]

The differnt grades of brake fluid have slightly different chemical compositions to achieve those grades. DOT3 is slightly different from DOT4, and DOT4+, and DOT5.1. There is a slight chance that the seal material in a brake system calling for DOT3 will have an adverse reaction if DOT4 is used.

That said, I use ATE DOT4+ brake fluid in the entire family fleet.


Ken

 

[Ray H]

Make sure you aren't comparing apples to oranges. Some fluids list "wet" boiling points, others, "dry". The latter will always be higher numerically in a Given DOT grade. Both are legitimate gauges of performance, but you need to be able to compare the numbers arrived at by the same testing methodology to arrive at a valid conclusion.

 

[Winston]

I have never seen a "generic" DOT 4 brake fluid. Most of the cheap brands are DOT 3 only. As mentioned it has to do with boiling point and its tendancy to absorb water. Valvoline Synpower is DOT 4, it is not synthetic. Castrol's fluid is DOT 4. I have not bought the boutique brands. I am happy to spend a couple extra bucks over the generic fluid to get Valvolines Synpower DOT 4. I dont think the boutique brands are worth it.

DOT 5 is a silicone based brake fluid that is incompatible with regular brake fluid. DOT 5.1 is a newer fluid that is compatible with regular brake fluid.