Dot 5.1

[Dell'Orto]

Now, shortly I'll be doing my brake system, and I want to use dot 5.1 brake fluid.
What hassles are there, and are there any special procedures needed to run dot 5.1 after previously using dot 4?

[Adamal]

As far as I know, all new DOT ratings that come out and 'compatable' with systems that use the previous rating.
They typically say "Use at least DOTX"

Much like oil!

[Lloyd]

But 5.1 is different. Why exactly do you want to use it? Its pretty much for race applications and thats about it.

[Malcolm]

yeah, there is very little reason to switch to 5.1 on a street car unless you want to be completely flushing the system annually

[85AW20v]

Have alook in FAQ - the post at the bottom of the list - all about brakes, fluids etc. Explains it all very simply.

[Dell'Orto]

Its not for the KE70 by any means

[pc]

Should be no problems using dot 5.1 I'm assuming you will be using synthetic and not silicon fluid.
The fluid just costs a bit more. Other than that, you probably wont notice any difference over dot 4.

[Dell'Orto]

Thing is, I do intend to give my car a bit of a burn round Manfeild once completed, maybe a few times even I'd like something that isnt going to boil itself into nothingness after 6 laps.
I figure heavyish car with a fair bit of power, its gonna get the brakes hot.
Still undecided as to which pads to use too, kinda leaning towards EBC green stuff.

[wde_bdy]

Race Brakes have what you need, ELF’s XT3167 . Their site also has a very detailed explanation of all the different fluid levels and other brake options. May be the same as whats in the FAQ from memory.

http://www.0800brakes.co.nz/

Have a chat to them about Mintex pads too.

Callum

[vvega]

5.1 is compatable with your exsiting fuilids
its not a silicon based fluid and dose not need to be flushed yearly
the most important aspect of 5.1 is it boiling point helping to reduce fade

:S

v

[TygerTung]

The problem with 5.1, is that it doesn't absorb moisture.

All braking systems produce moisture, and since it's not abosorbed, you'll just have a bit of water in there. This will boil very easily, so then you'll just get bad brake fade.

I'd recomend a good racing dot 4 fluid.

You can get Motul factory line Racing brake fluid for a decent price.

[pc]

The problem with 5.1, is that it doesn't absorb moisture.

Only if it's silicone based, as it's not, then it will absorb the moisture. dot 5.1 has a slightly higher boiling point than dot 4 so in theory it will be better.
I personally think all brake fluids should be flushed yearly, but that's just personal preference.

[wde_bdy]

The problem with 5.1, is that it doesn't absorb moisture.

You are confused with DOT 5, which is silicone based. DOT 5.1 is generally for synthetic (not silicone) fluids and is the highest rating available.

Callum

[vvega]

100% correct
but in saying that i belive the silicone based product is still better
5.1 is great fuild used it in my bikes for years with much hard abuse cabt rate it highly enough

and yes 5.1 is hydroscopic

braking systems dont produce mositure they absorb it...hence hydroscopic.........

anywasy back to the mindless babble

[Dell'Orto]

but in saying that i belive the silicone based product is still better

Why is that? I was lead to believe it makes the pedal kinda spongy due to the compressability of the fluid?

[Truenotch]

Brad never use silicone brake fluid!!! Have a look on the ebc site theres some stuff about what yoou should and shouldn't use, silicone fluids is not supposed to be used because when the brakes get hot the water produced gets trapped and makes the padal do nought.

[Truenotch]

http://www.0800brakes.co.nz/pg8.htm

Looks like dot 5.1 would be sweet.

[vvega]

but in saying that i belive the silicone based product is still better

Why is that? I was lead to believe it makes the pedal kinda spongy due to the compressability of the fluid?

from my understanding silicon fuild is spose to be changed on a per meeting basis
silicon also ahs a trumendously high boiling point ...obviously dependant on what you buy as per anything

you also cant mix the 2 fuilids tends to turn to stringy slimmy stuff

v

[Perky]

You are confused with DOT 5, which is silicone based. DOT 5.1 is generally for synthetic (not silicone) fluids and is the highest rating available.

Exactly. 5.1 was obviously a bloody stupid name to use since it always causes this confusion. I take it that the DOT numbers were originally intended to specify the fluid's characteristics rather than its composition -- but then they were also supposed to guarantee compatibility . Presumably this is why some brands, such as Castrol, market a Super DOT 4, which they recommend for applications requiring DOT 5.1. The DOT boiling points are actually minimum values, so a DOT 4 can have the same or higher boiling points as DOT 5.1. I use DOT 5.1 because it is also supposed to be a bit thinner and more suitable for ABS equipped systems, but I doubt that anyone has ever had a problem using DOT 4.

[dimmy]

i can't remember the exact reason but once you go to dot 5.1 you can't go back to dot 4, i'm 97% sure of this.