accidently bought dot 3 brake fluids and have been running it for about month, just started to notice my brake fluid heats up faster..... i just bought new dot 4 will be flushing the dot 3 out tomorrrow.

is dot 3 bad for the system or is it just the boiling point that is higher between the two?

 

boiling points are diffferent , but if it was silicone based the that might gum it up

 

The difference between the DOT (Department of Transportaion) ratings of brake fluid are the boiling point ranges that they achieve both dry (no water absorbed) and wet (about 3-4% water content). For DOT 3 the dry boiling point is at least 401 and the wet 284 degrees. DOT 4 raises the bar to 446 and 311 respectively. Those are the DOT ratings mind you , and there are high performance brake fluids that exceed those ratings.
The cost of brake fluid can vary as well from less than $0.20 an ounce to over $2.00 an ounce. Some of the high performance fluids are rated well over 500 (to almost 600) degrees boiling point dry. Wet boiling points will also vary, but be well over 400 degrees.
The higher boiling points are critical to those of you that wish to spend time on a race track. Once you boil your brake fluid it will not recover and you MUST bleed and change out the fluid.
The every day driver will find brake performance just fine by sticking with the fluid that the dealership recommends unless they use their vehicle to the extreme, such as a newspaper delivery route or negotiating their way down curvy mountain roads. You will know because the brake pedal will start to feel mushy as the fluid overheats and the pedal may even go to the floor.
So what is the big deal? The big deal is that most of us never flush and replace our brake fluid. In fact, if you go to a garage and have a “brake job” done it is highly unlikely that they will do much more than bleed the brake lines. This means that the old - water soaked - tired - brake fluid will still be there. The water can react to oxidize brake components from the inside out. What you should do, probably once a year, is have the old fluid flushed and completely replaced with fresh brake fluid.


one of the first things i do to any bike i own is switch to Motul DOT 5.1 brake fluid. They claim the boiling point of their fluid is 600F. i personally have never experienced any "brake fade" using their brake fluid and nor have any of my friends that use it.

i actually just replaced the brakes (pads and rotors) earlier tonight, on my girls honda and switched her fluid to DOT 5.1 too. its cheap insurance if you ask me.

 

mixing them two wont damage anything,but any other would..

 

oh, yeah, i forgot to mention DOT 5.1 is also compatible with DOT 3 and 4.

 

i thought 5.1 had silicone in it ? if so it is not good for a dot 4 system ...

motul rbf 600 has a 600 degree boiling point and has no silicone in it...

 

nope DOT 5.1 is mixable with DOT 3 and 4, DOT 5 is the silicon based brake fluid

I always use DOT 5.1, never have any problems with brake overheating!

 

+1 DOT 5, has silicone in it, DOT 5.1 does not.

 

what the average boiling point on 5.1?

 

 

did you ever try using tranny fluid ??

 

wtf

 

thats what im running now

 

yeah, in my power steering pump.

 

have fun when your brakes take a ****.

 

that fluid has a much higher boiling point , and why would it make the brakes crap out ??

 

i don't know if this matters or not but tranny fluid has a **** load or detergent in it and could harm the rubber parts in your masters

 

People are always trying to get nuts with brake fluid.

Just run quality Dot 4 and call it a day.

 

rog, do you remember seeing the color of my fluid ???

 

brake fluid does not compress.

+1