Brake Fluid

[964RS]

Use ATE Super Blue racing. DOT 4. It's excellent on the track. []

 

[Riverside]

ORIGINAL: 964RS Use ATE Super Blue racing. DOT 4. It's excellent on the track. []

Completely agree, I tried dot 5.1 (generic & branded) after my brakes overheated at my first trackday, they still boiled just the same. Now use Racing Blue & haven't boiled it since, it's no longer the weakest link, and I've had no problems (that I wouldn;t otherwise have had) with the fluid in normal use either. Then I started to get a hard 'dead' pedal from heatsoak (pads/disk too hot), added the early turbo brake ducts & they no longer overheat at all. Standard pads (so far) too []

 

[AntB]

So this stuff is good for normal road use also and normal regular change intervals?

 

[Riverside]

ORIGINAL: AntB So this stuff is good for normal road use also and normal regular change intervals?

It should last about a year, yes.

 

[eastendr]

Castrol SRF ....

 

[AntB]

So - ive not long had a complete brake fluid change and the fluid is as clean as is....

But I just wondered what you guys used??... I guess the more common is DOT 4... When I ran my very modded Saab 9000 which had yellow stuff pads and brembo disks - I changed the fluid to DOT5.1 (dont use DOT 5!) and the brake feel straight away was MUCH better on track and road use.

Just wondered if anyone has used DOT5.1 in there 944 and how much better it was over DOT4?

Cheers A

 

[edh]

No need to buy anything expensive for road use - any dot 4 should be fine. I use Motul RBF 600, bu that's for track use. I wouldn't bother spending the extra for the road. Brake feel is very different with new pads - travel gets much longer with well worn pads.

 

[Peter Empson]

ORIGINAL: eastendr Castrol SRF ....

Same here, I boil the ATE fluid, but SRF is fine (I think it still boils/overflows slightly, but the pedal stays firm). I'm led to believe it is quite hygroscopic, so a yearly change is recommended (or more regularly if you race of course). I used to use Castrol Response (a cheaper option) and that was good too, but not in the same league as SRF.

 

[AntB]

Yeah - was just mainly interested if people had noticed a diif between DOT4 and DOT5.1 for 'fast' road use as I did in my saab (which my son named KITT... lol jeez tho it was quick - it was the 'Turbo Boost' that did it for him..)

 

[tr7v8]

Be careful trying DOT 5.1 in some cars it can swell the seals, some Alfas suffer this. If I ever rebuild mine completely I'm going Silicone which is DOT 5 no hassle with moisture & rusty brake bits! I've run it in the past & had no problems & a guy who sprinted a Cat 7 used it again no issues.

 

[Hilux]

No need to buy anything expensive for road use - any dot 4 should be fine

True 5.1 is hygroscopic (absorbs water) so needs changing every year. ATE blue or SRF if tracking the car

 

[944Turbo]

Dot 4 is hygroscopic, didn't know dot 5.1 was as well, being synthetic I assumed they might have sorted this (DOT 5 is silicone and not) . I use halfords 5.1 I believe its the same as the Castrol 5.1 - certainly same shape bottle and identical specs. I found when hot it expands, at the Nurburgring with reasonably fresh pads and fluid (about 1000 miles) it expanded enough to overflow the cylinder. I use it on road and track and havent had any issues I change it every couple of years. I quite like EBC yellows as well as a road /track compromise but maybe I am less hard on the brakes than some. (hate Reds though) Tony

 

[Hilux]

Dot 4 is hygroscopic, didn't know dot 5.1 was as well

Its not [8|][8|] its a typo, sorry - Note to self: must not rush type when replying

 

[tr7v8]

ALL brake fluid is hygroscopic except Silicone, hence needing to be changed regularly.

 

[barks944]

Any negatives to using silicone?

 

[944 man]

It doesnt mix with other glycol-ether brake fluids. DOT5 is silicone but DOT5.1 is mineral based, like DOT4 et al...

 

[944 man]

Remember too that even if you can completely clean the system of glycol-ether fluid then silicone fluid (so that your seals wont give leading to total brake failure!) isnt suitable for use in a car equipped with ABS.

 

[944 man]

ORIGINAL: Hilux

Dot 4 is hygroscopic, didn't know dot 5.1 was as well

Its not [8|][8|] its a typo, sorry - Note to self: must not rush type when replying

You were right originally: DOT5.1 fluid IS hygroscopic. DOT5 is silicone based and it isnt hygroscopic, but it isnt compatible with cars previously run using mineral fluids.

 

[barks944]

Is it ok to swap over to silicone if you dont have ABS then?

 

[944 man]

Not really no, because the two fluid types dont mix. If youre happy that you can completely and absolutely flush your system of mineral based fluid then it will work perfectly well, but how can you do that? Id use 5.1 which will mix and has a higher boiling point.