brake fluid-what and why?

[Rsv1000R]

Dot 5.1 is sometimes compatable with Dot 4 systems. Dot 5 is not the same as 5.1 nor do they mix. My HD has Dot 5, and my Aprilia says Dot 5.0 (4.0 compatable) which I think is what they call 5.1 in Europe.

[tommymac]

Originally Posted by Rsv1000R

Dot 5.1 is sometimes compatable with Dot 4 systems. Dot 5 is not the same as 5.1 nor do they mix. My HD has Dot 5, and my Aprilia says Dot 5.0 (4.0 compatable) which I think is what they call 5.1 in Europe.

I will have to double check but am 99% sure the futura used dot 4 for the brakes and the clutch.

Tom

[NONE_too_SOFT]

Use whats called for w/ the specific brake system you have. if you've got aftermarket parts on your brakes i'd consult them, rather than what the OEM calls for.

I've heard that using High Temp DOT 5 will reduce Spongy feel during intense/frequent braking. have yet to test it, but i've got some in the mail.

[Rsv1000R]

Originally Posted by NONE_too_SOFT

Use whats called for w/ the specific brake system you have. if you've got aftermarket parts on your brakes i'd consult them, rather than what the OEM calls for.

I've heard that using High Temp DOT 5 will reduce Spongy feel during intense/frequent braking. have yet to test it, but i've got some in the mail.

If you're getting US Dot 5, be careful about mixing it with even a trace of Dot 4, as it turns to goop. There a whole procedure for switching it over you need to follow.

Dot 5 doesn't absorb moisture, which reduces the boiling point of Dot 4 brake fluids, But your brake system will still collect condensation, and then you get water settling to the lowest point it can get to, and if it gets into the calipers, you still boil it, and it corrodes everything it touches.

Apparently, there have been a lot of expensive cars that had dot 5 put in during restorations, and had the brake systems ruined from condensation.

[ZUKIMON]

I'm still unsure about my fluid. My 929 says DOT 4 on the caps, and I have a quart of DOT 4 Castrol Synthetic sitting here on my workbench at work. Is there a DOT 4 that's not synthetic? Will this be OK in my bike? I've never messed with anything other than DOT 3.

[racedoll]

I use whatever it says to use.

[zed]

Originally Posted by ZUKIMON

I'm still unsure about my fluid. My 929 says DOT 4 on the caps, and I have a quart of DOT 4 Castrol Synthetic sitting here on my workbench at work. Is there a DOT 4 that's not synthetic? Will this be OK in my bike? I've never messed with anything other than DOT 3.

without looking it up somewhere I don't know the answer, did you look on the container and see if it says not to mix with other DOT4 fluids?

[ZUKIMON]

I'll quote it when I get back to work tomorrow, but it never stated that it either could not mix, or could mix with DOT 3/4 fluid. ??? That's what threw me....

I mean, my cap says DOT 4, and this fluid is DOT 4 Synthetic. How do I know if mine is synthetic or not and if they will combine if mine isn't. I'm at a loss on this one. Can you even get DOT 4 that's not synthetic?