Brake fluid change

[Dell'Orto]

The Repco stuff is Silverline branded, it works plenty well for road cars, and would probably be pretty good for track cars that dont weigh 1500+kg.
Part of the dot rating of brake fluid is the minimum requirement of temperature resistance it has, hence why you can get dot 4 that can out perform dot 5.1.

[xsspeed]

Silver line thats the one.

So is dot 5 ok to chuck in the clutch hydraulic system?

[touge rolla]

It's fine in mine. Not necessary though as clutch fluid hardly gets hot

[xsspeed]

Sweet, figured that it wouldn't get hot, was more asking about the moisture absorption?

[rollaholic]

i think the comment made previously about moisture absorption was due to DOT 5 traditionally being silicon based, which allowed it to have a higher boiling temperature but means its unable to absorb water (no hygroscopic qualities) which is fine as long as its changed regularly. if not moisture can build up and form pockets in the braking system, if these boil vapor lock occurs very easily. this type of fluid is generally used in dedicated race cars.

whereas traditional (DOT 3 & DOT 4) brake fluid actually being glycol based absorbs moisture, (hygroscopic) which gradually lowers its overall boiling point but generally gives it a much longer service life.

DOT rating relates to boiling points, both 'wet' (fully saturated with H2O) and 'dry' or brand new. to the best of my knowledge glycol based brake fluids have not been able to achieve DOT 5 levels, though from whats been posted above it sounds like this DOT 5.1 stuff is actually glycol based. perhaps someone a bit more up to speed will confirm this.

[Dell'Orto]

Dot 5.1 is glycol based