Dot 4 or "Dot 3 & 4 Synthetic"

[Skeeve]

As mentioned, but to elaborate, the dry boiling point accurately reflects the boiling point of the fluid. But being hygroscopic, it absorbs water.[snip]

 

A lot to be said for some of the push-bike disc brake systems settling on mineral oil; actively repels water, keeps the parts lubed!

 

Of course, it may have too great a coefficient of expansion to be used in a brake system that heats up a lot; push-bikes aren't known for heat-related brake fade...

[GuzziMoto]

A lot to be said for some of the push-bike disc brake systems settling on mineral oil; actively repels water, keeps the parts lubed!

 

Of course, it may have too great a coefficient of expansion to be used in a brake system that heats up a lot; push-bikes aren't known for heat-related brake fade...

Some KTM's use mineral oil in the hydro clutch. Not sure how well it would cope with the 400 plus degrees that can be generated by stopping a 500 lb Guzzi, but you do not want to mix and match the two. DOT 5 is the same way with water, but it is not incompressible (is that a word?). That results in a soft lever. No one wants a soft lever, do they?

[gavo]

Breakfluid is hygroscopic. So the dry boiling point applies as long as the fluid is freshly filled up from a sealed container only.

When the B/F will have become wet depends on several things. The climate you're located in, how well sealed your brake system is and so on. I think changing the fluid every two years or so is a proper interval to keep you on the safe side. But remember - the B/F is hygroscopic also in the can you bought it in. The water saturation level can be determined by a good shop, by the way.

 

Hubert

 

Yea I know it's hygroscopic, so how do they arrive at the wet boiling point , must the fluid contain a certain pecentage of water to be classed as unsafe , how do the calculate it

[Dan M]

Yea I know it's hygroscopic, so how do they arrive at the wet boiling point , must the fluid contain a certain pecentage of water to be classed as unsafe , how do the calculate it

 

 

Measured at 3% water content.