is DOT4 ok for S2?

[tom]

is it ok to use ordinary DOT4 fluid or S2 need some extra one? i am not talking about high performanc e fluids, just standard one to use.

[Corey]

yeah. Make sure you buy a bit extra so that you know you have flushed the old fluid out.

[rotoryboy]

I thought it was Dot 4, Dot 5 and Dot 5.1

[Corey]

Oops. My mistake, I got carried away with the typing you are correct.
The choices are DOT 3,4,5 and 5.1 out of them 5 is a silcone fluid and is not recommended.
As a minimum you want to use DOT 4 but I would suggest you use DOT 5.1, I do. The downside to 5.1 is it requires bleeding more frequently but it performs better.

[caterpillar]

dot 4,0 or 5,0-5,1

use dot 5,0 or 5,1 for the brakesystem and clutch.it will not take the vater from air,and less rust...and higher temprestistent....use ONLY audi's g02000 for the servo,and hydrolic brakeservo

[peteV6TDI]

don't use dot 5 it's silcone and will kill all rubber parts and end in tears

[Alistair C]

use dot 5,0 or 5,1 for the brakesystem and clutch.:

..... from what I remember, DOT 4 is recomended as standard, DOT 5.0 is a DEFINATE NO GO and DOT 5.1 is an acceptable modern equivalent with some benefits (and is miscable with any DOT 4 which may already be in the system).

Basically - avoid DOT 5.0 at all costs!

[caterpillar]

dot 5,1

use dot 5,1 no prob in 7 years......

[Corey]

use dot 5,1 no prob in 7 years......

Ditto

[dan_b]

On no account ever use DOT 5.0 in the S2, NO NO NO!

DOT 4.0 is the default fluid, but there are DOT4s that have better boiling points to so-called DOT5.1s, it's a minefield out there...

[pixsaudisex2]

dot 5

i read that you say dot 5 fluid is no good as it eats the rubber seals how can this be when you can even spary silicon brake fluid all over your car and it wont even wreck the paint work an yet a wee bit of brake fluid and well bye bye paint..

and every thing is silicon based nowdays so can it really be that bad as it is the best all peformance places use it an well surely they use it for a reason and dont it last for ever as well.. hey i also know you shouldnt i had it in a mark one golf for nearly two years and never had a problem and althought the mark one is low tech compared to the audi brakes but surely i should have had a problem with it ... i also know that ap lockhead make it say its the best fluid you can get but not to use it with any of there products .. o an happy new year...

[dan_b]

DOT 5 is wierd stuff: as you say it doesn't rot paint like traditional brake fluids, and also unlike traditional brake fluids, it doesn't absorb water (ie. it's not hygroscopic). This may sound like a good thing, but in fact it's a bad thing - instead of the water mixing with the fluid, it stays as water in the system, and when that heats up, it boils, leading to gas in your brake fluid, which means spongy pedal, brake fade and ultimately impaired braking . Water hanging around also means corrosion of your brake components from the inside out.

DOT 5.0 is also utterly immiscible with non-silicone-based fluids like DOT4 and DOT5.1 - if you bung it in, you get two completely separate layers of fluid in your brake system. Again this is bad.

Silicone fluids can be made to have very high boiling points, which is why its often used in racing, but racing cars also generally change their fluids every race. Do you want to bleed your system every time it rains?!

I'm told that it also messes up things like the ABS and can rot the brake line seals in the S2 - this is because if the seal components are not made of natural rubber, the silicone eats it. I presume therefore that the sealant bits in our brake system are not natrual rubber.

The other confusing thing is some very expensive high performance fluids, like Castrol SRF - (probably the best brake fluid out there, but it's also >£50 a tin), do actually contain silicone esters, but they're not silicone-based, if that makes sense! (I imagine this is why when you change to Castrol SRF you have to flush the system completely with SRF and then re-fill with clean SRF).

DOT5.1 is not necessarly "Better" than DOT4 either - for example, ATE Super (also known as Type 200) is "only" a DOT4 classified fluid, but it far exceeds the temperatures required to meet DOT5.1. Go figure!