Silicone brake fluid & demon tweeks discount

[pete_griff]

Not sure if any of you will have experience with this stuff already (marky mark....) but, I'm in the process of rebuilding a saxo for a friend of mine as he recently bought a vx220 and he decided that he loved his old car too much to get rid of, so he wants me to eventually turn it into a 200hp piece of trackday lunacy, which is fine by me as i get a project without even having to pay for it - ideal

Anyway I havent actually had the chance to use the fluid in practice yet as I havent got the struts back yet as they are having new bearings pressed in by a friend as I speak.

However the fluid he's using is by automec - its got a high boiling point (about 260 degrees C i think), it won't destroy paintwork like ordinary stuff (have proved this on a old bit of panelwork!), and the best thing is, unlike normal "anhydrous" fluid it doesnt attract water, hence doesn't slowly get a lower boiling point like the ordinary stuff, so giving very consistent performance. The coolest thing about it is that its a real nice deep blue in colour, which is unusual for brake fluid as its normally yellowy/green...

The point of this thread though, is that if you are changing over to braided hoses (e.g. goodridge) as i will be sometime in the future, you may want to consider it, depending really on how much you cain your brakes and how long you plan on keeping the car...

If any of you want to use it I know it's available (not cheap though - about

[pete_griff]

by the way i'm sory that i wirte an essay for you all to read each time

[The Swede]

What's the advantage of using this brake fluid over normal 5.1 fluid ?

[pete_griff]

basically normal fluid is "anhydrous" which is a chemical term roughly meaning "without water". because of this normal fluid attracts water over time which lowers it's boiling point, which is the reason that the fluid has to be changed every so often. Also normal fluids, unless you go for a performance brand (e.g. AP racing's fluid), have a lower boiling point than the silicone stuff and as the silicone stuff is performance orientated it also has a high boiling point.
Obviously if the fluid boils in the lines from getting too hot due to excessive braking then you will have air in the lines which equals very spongy pedal feeling and little to no braking power!
Hence silicone fluid gives consistent performance and it never really needs to be changed as it doesnt degrade over time like normal fluid. Also its alot nicer to handle as it wont destroy your paintwork.

Point to note - dont just add it to your normal fluid as it almost definitely wont mix. If you do want to use it, then the old stuff has to be drained out, the system flushed with the new fluid and then refilled; like i said previously a good time to do this is when changing the hoses if you are going to do it, as the brakes will need to be bled then anyway.

[chelspeed]

Anhydrous is the wrong word, brake fluid is hygroscopic, it attracts water from the air, anhydrous just means it's not mixed with water before you start.

The fact that silicon fluid is not hygroscopic is of limited benefit because the silicon fluid itself is squishy. Normal brake fluid gets squishy when it attracts water which then turns to steam when it gets hot in the brakes, it's nothing to do with air in the fluid. Having brake fluid that's OK to 200 deg C is of little benefit when it's full of pockets of compressible steam. But you can easily solve this by changing the fluid regularly, every couple of years for normal brake fluid or annually for the more specialist racing fluids which happend to be more hygroscopic than normal fluids.

See AP Racing's view of silicon brake fluid here. Don't be tempted stick to normal brake fluid.