Evening all,

I've just been having a discussion about hydraulic fluid (brake and clutch) with a mate, and I'm after a bit of advice.

I've got one donor part that I want to use (clutch slave cylinder), and the rest are either new or reconditioned parts (wilwood master cylinders, sierra brake calipers).

As I understand it there are two types of hydraulic fluid that I can use. Either common glycol stuff, or silicone type stuff. Now, apparently silicone is sometimes not compatible with the rubber seals on various hydraulic components?

I'm a little confused as to which type of fluid is the best stuff to use, and which I should go for on my car? AS I am using a donor slave cylinder, is there an easy way to identify what fluid has been used in it previously? There is still a bit in the bleed pipe that I can drain to test.

If anyone has any decent links to good sites that explain the differences/pro's and con's I'd love to see them!

Cheers
Andy

Have a look at this thread

http://locostbuilders.co.uk/viewthread.php?tid=17577

HTH

Mark

A good thread, in reality unless you are doing something REALLY silly, then PROPERLY MAINTAINED DOT 4 fluid will be fine.

Too many people blame braking problems on the fluid when it has been in the car for three years!!!!! DOT 4, changed every year, is fine.

I have done road rallies and maintained several stage rally cars (tarmac rallying puts massive stress on brakes) and never boiled DOT 4.

Yes I have had brake fade, but that was pad fade (solid pedal +no brakes) not fluid fade (pedal soggy then goes to the floor next push)

If you want decent brakes, the steps are really very simple,
1) appropriately sized calipers

2) appropriately sized, good quality and regularly changed or skimmed discs

3) Mintex 1144 pads (or race ones if you are racing!)

4) regularly changed good- ol' DOT 4 or super DOT 4 fluid.

Simple as that.

I must have missed that thread when I did a search!

I think that going for the DOT4 fluid is probably going to be my best bet. I don't like the sound of the fluid collecting water in droplets, leading to corrosion. As the car will be serviced regularly, flushing the fluid through once a year is not that big a deal.

DOT4 it is then!

PS. anyone know if powdercoat is eaten by brake fluid?

Cheers
Andy

I think so, but not as quickly as paint is

Hi,
I use Castrol Response Super Dot 4 fluid. I got mine in Halfords although I'm sure you can get it cheaper elsewhere. A quick search on google found this website which shows a photo and a brief spec. It is the second item down "Super Dot 4" not the "Dot 4" item.

Note: be aware that Dot 5.1 is NOT compatible with Dot 5. Dot 5 is the silicon stuff whereas Dot 5.1 is compatible with Dot 4.

I used Castrol response in my 240BHP (Tweaked) Rover Vitesse Turbo with Black Diamond grooved and drilled discs and EBC Greenstuff pads. The brakes were awesome and never faded in the slightest despite serious abuse.

[Oh, one other thing. I'd flush all donor cylinders out with methelated spirits and replace all seals before reusing any donor brake parts. Also, once you have reconditioned the parts, try to keep good clean fluid in the system as it will protect the seals and prevent corrosion.]

HTH,
Craig.


[Edited on 20/4/2005 by craig1410]