Glycol or silicone based brake fluid?

[chiroman]

Was googling re brake fluids and found this site, well worth a read.

http://www.motorcycleproject.com/motorc ... fluid.html

and this:

http://www.american-auto-club.co.uk/aac ... show&id=70

[asperformance]

IMO never ever buy a dot5 silicone b/fluid - these days its mostly aimed at military applications and shouldn't be used in a road car, also be aware that it can attack certain seals in the system

** this is not to be confused with dot5.1 which is specifically an ABS fluid and can in some manufacturers have a performance advantage which is perfectly fine to use **

[chiroman]

The two articles were educational for me as although I've had Halfords dot 5.1 in WR1 for a couple of years on the basis of a higher boiling point I also thought, mistakenly, dot 5.1 was a silicone fluid and and thus wasn't hygroscopic.
However, as you say, its the dot 5 which is the silicone fluid and not hygroscopic whereas the dot 4, & 5.1 are the glycol fluids and will absorb the water vapour and dropping the boiling point.
So I'll be replacing the dot 5.1 with new when convenient as its a couple of years old.

[hightower]

i use glycol, some weeks no toppoing up required some weeks have to use loads........













It is great for drying out gas on an oil rig

[chiroman]

I used to design north sea oil & gas platforms!