Romanator

iTrader: (13)

Sometime this week I plan to change my brakes (discs and pads and SS brake lines) and completely flush my brake fluid. And I was considering using DOT 5 brake fluid for my brake and clutch master cylinders.
Does anyone here use dot 5 brake fluid for the brake and or clutch master cylinders ?
Is it safe to use ?
Or does everyone stick to traditional DOT 3 or 4 ?

need RX7

iTrader: (4)

Stick with 3 or 4.

Sojin

Well if u dont know what the diff is, it is a syn so it dose not absorb water so u dot have to bleed it and when heated it dose not change the volume as much but the only thing is u have to for the most part have everything brand new if not it can turn to jello

Sojin

and fyi if your not full out racing or somehting like that keep with the dot 3

Turbo II Rotor

iTrader: (2)

Dot 4 will work in a dot 3 system IIRC. Your temps won't get high enough to boil Dot 4.

Black91n/a

DOT 5 is silicone based and should not be used. DOT 5.1 can be used, but is un-necessary. If you're not getting fade, there's no reason to upgrade. Also, keep in mind that a DOT4 fluid doesn't necessarily have a higher boiling point than a DOT 3 fluid, the specification is for MINIMUM boiling temps.

RETed

If you can't put together a decent sentence that can pass the 5th grade, I'd suggest you STFU.
I can't even understand WTF you're trying to say, and I have a feeling you have no idea WTF you're talking about.


-Ted

Apex944

iTrader: (10)

+1
Do not use DOT 5 brake fluid on a street driven car.
The silicone based fluid does not absorb moisture/water from your system meaning your system will rust from the inside out from the water collection.

DOT 5 is meant for all out racing vehicles who change their brake fluid after every race.

DOT 4 is what your are looking for to use if you think you'll reach that kind of temperature. I believe DOT 4 is rated at 450 or so degrees Fahrenheit for it's boiling point which unless your tracking your car I doubt you will ever reach.

Snailz

Umm why has no one mentioned that it will probably dry out all your seals and completly destroy your brake system? Plus there's the rust issue.

Romanator

iTrader: (13)

Ok, so from what I've read above. My goal is to have a track car but right now track racing is out of the question so I'm gonna stick to DOT 4 since right now I'm gonna use my FC in the street as my rest of the season weekend car. Thanks for the tips.

BTW
I knew DOT 5 was silicon based, and I knew it has a higher boiling point. I just wasn't certain if it's safe to use in a steer car and to keep the fluid in the system while my car goes back to storage in about a month and a half from now. So forgewt that idea of using DOT 5. Thanks guys.

Pinfield357

Just a little FYI i sell tons of DOT 5 fluid to the post office. They use it in thier LLVs

Black91n/a

They were probably designed for it, the FC was not, therefore it should not be used in an FC.

turboeric

There is tons of experience with DOT 5 silicone fluid in the British car community, where it works very well with cars that don't get driven much. It doesn't absorb water and no, that doesn't mean your calipers rust out. It means they don't.

To use DOT 5, the system must have no trace of any glycol based brake fluid in it (i.e. DOT 3, 4 or 5.1). At a minimum, it must be thoroughly flushed with methanol, but it is best to start with a freshly rebuilt system. I'm not aware of anyone using it in racing, as it is more compressable than glycol and gives a spongy pedal. I recently drove a 70 Datsun 240Z with silicone brake fluid, and the brakes felt awful. Stopped OK, but very soft. Since racers bleed their brakes routinely, the moisture absorbtion characteristic of racing brake fluid are all but irrelevant.

Also be aware that the DOT 3, 4 specs are minimum dry boiling points and that not all fluids are compounded to the minimum. DOT 3 has a minimum dry bp of 400F, but you can buy DOT 3 with a dry bp of 550F. DOT 3 and 4 are completely safe to mix, by the way - it's part of the standard.

If you have a street car that isn't driven much, then Castrol LMA brake fluid is a good choice. It is formulated for Low Moisture Absorbance, which it does well.

shika805

iTrader: (1)

just stick to DOT 3 or 4, simple as that...